Initial.

kotlin-textfiles-skeleton/build.gradle

@@ -0,0 +1,50 @@
+import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
+
+buildscript {
+    ext.kotlin_version = "1.9.0"
+    ext.jvm_version = 17
+    ext.kotlinter_version = "3.15.0"
+    repositories {
+        mavenCentral()
+    }
+    dependencies {
+        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
+    }
+}
+
+plugins {
+    id 'application'
+    id 'org.jetbrains.kotlin.jvm' version "$kotlin_version"
+    id 'org.jmailen.kotlinter' version "$kotlinter_version"
+}
+
+group = 'uk.ac.ic.doc'
+version = '1.0.0'
+
+description = """Kotlin Text Files"""
+
+tasks.withType(KotlinCompile).configureEach {
+    kotlinOptions {
+        jvmTarget = "$jvm_version"
+    }
+}
+
+java {
+    toolchain.languageVersion.set(JavaLanguageVersion.of(jvm_version))
+}
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
+    testImplementation "org.jetbrains.kotlin:kotlin-test-junit:$kotlin_version"
+    testImplementation "org.jetbrains.kotlin:kotlin-reflect:$kotlin_version"
+}
+
+test {
+    testLogging {
+        events "PASSED", "FAILED", "SKIPPED"
+    }
+}

kotlin-textfiles-skeleton/gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,7 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.2-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists

kotlin-textfiles-skeleton/gradlew

@@ -0,0 +1,248 @@
+#!/bin/sh
+
+#
+# Copyright © 2015-2021 the original authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+##############################################################################
+#
+#   Gradle start up script for POSIX generated by Gradle.
+#
+#   Important for running:
+#
+#   (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is
+#       noncompliant, but you have some other compliant shell such as ksh or
+#       bash, then to run this script, type that shell name before the whole
+#       command line, like:
+#
+#           ksh Gradle
+#
+#       Busybox and similar reduced shells will NOT work, because this script
+#       requires all of these POSIX shell features:
+#         * functions;
+#         * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
+#           «${var#prefix}», «${var%suffix}», and «$( cmd )»;
+#         * compound commands having a testable exit status, especially «case»;
+#         * various built-in commands including «command», «set», and «ulimit».
+#
+#   Important for patching:
+#
+#   (2) This script targets any POSIX shell, so it avoids extensions provided
+#       by Bash, Ksh, etc; in particular arrays are avoided.
+#
+#       The "traditional" practice of packing multiple parameters into a
+#       space-separated string is a well documented source of bugs and security
+#       problems, so this is (mostly) avoided, by progressively accumulating
+#       options in "$@", and eventually passing that to Java.
+#
+#       Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS,
+#       and GRADLE_OPTS) rely on word-splitting, this is performed explicitly;
+#       see the in-line comments for details.
+#
+#       There are tweaks for specific operating systems such as AIX, CygWin,
+#       Darwin, MinGW, and NonStop.
+#
+#   (3) This script is generated from the Groovy template
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       within the Gradle project.
+#
+#       You can find Gradle at https://github.com/gradle/gradle/.
+#
+##############################################################################
+
+# Attempt to set APP_HOME
+
+# Resolve links: $0 may be a link
+app_path=$0
+
+# Need this for daisy-chained symlinks.
+while
+    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+    [ -h "$app_path" ]
+do
+    ls=$( ls -ld "$app_path" )
+    link=${ls#*' -> '}
+    case $link in             #(
+      /*)   app_path=$link ;; #(
+      *)    app_path=$APP_HOME$link ;;
+    esac
+done
+
+# This is normally unused
+# shellcheck disable=SC2034
+APP_BASE_NAME=${0##*/}
+APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD=maximum
+
+warn () {
+    echo "$*"
+} >&2
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+} >&2
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "$( uname )" in                #(
+  CYGWIN* )         cygwin=true  ;; #(
+  Darwin* )         darwin=true  ;; #(
+  MSYS* | MINGW* )  msys=true    ;; #(
+  NONSTOP* )        nonstop=true ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD=$JAVA_HOME/jre/sh/java
+    else
+        JAVACMD=$JAVA_HOME/bin/java
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD=java
+    if ! command -v java >/dev/null 2>&1
+    then
+        die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+fi
+
+# Increase the maximum file descriptors if we can.
+if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
+    case $MAX_FD in #(
+      max*)
+        # In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC3045
+        MAX_FD=$( ulimit -H -n ) ||
+            warn "Could not query maximum file descriptor limit"
+    esac
+    case $MAX_FD in  #(
+      '' | soft) :;; #(
+      *)
+        # In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC3045
+        ulimit -n "$MAX_FD" ||
+            warn "Could not set maximum file descriptor limit to $MAX_FD"
+    esac
+fi
+
+# Collect all arguments for the java command, stacking in reverse order:
+#   * args from the command line
+#   * the main class name
+#   * -classpath
+#   * -D...appname settings
+#   * --module-path (only if needed)
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and GRADLE_OPTS environment variables.
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if "$cygwin" || "$msys" ; then
+    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+
+    JAVACMD=$( cygpath --unix "$JAVACMD" )
+
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    for arg do
+        if
+            case $arg in                                #(
+              -*)   false ;;                            # don't mess with options #(
+              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+                    [ -e "$t" ] ;;                      #(
+              *)    false ;;
+            esac
+        then
+            arg=$( cygpath --path --ignore --mixed "$arg" )
+        fi
+        # Roll the args list around exactly as many times as the number of
+        # args, so each arg winds up back in the position where it started, but
+        # possibly modified.
+        #
+        # NB: a `for` loop captures its iteration list before it begins, so
+        # changing the positional parameters here affects neither the number of
+        # iterations, nor the values presented in `arg`.
+        shift                   # remove old arg
+        set -- "$@" "$arg"      # push replacement arg
+    done
+fi
+
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command;
+#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
+#     shell script including quotes and variable substitutions, so put them in
+#     double quotes to make sure that they get re-expanded; and
+#   * put everything else in single quotes, so that it's not re-expanded.
+
+set -- \
+        "-Dorg.gradle.appname=$APP_BASE_NAME" \
+        -classpath "$CLASSPATH" \
+        org.gradle.wrapper.GradleWrapperMain \
+        "$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+    die "xargs is not available"
+fi
+
+# Use "xargs" to parse quoted args.
+#
+# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
+#
+# In Bash we could simply go:
+#
+#   readarray ARGS < <( xargs -n1 <<<"$var" ) &&
+#   set -- "${ARGS[@]}" "$@"
+#
+# but POSIX shell has neither arrays nor command substitution, so instead we
+# post-process each arg (as a line of input to sed) to backslash-escape any
+# character that might be a shell metacharacter, then use eval to reverse
+# that process (while maintaining the separation between arguments), and wrap
+# the whole thing up as a single "set" statement.
+#
+# This will of course break if any of these variables contains a newline or
+# an unmatched quote.
+#
+
+eval "set -- $(
+        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+        xargs -n1 |
+        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+        tr '\n' ' '
+    )" '"$@"'
+
+exec "$JAVACMD" "$@"

kotlin-textfiles-skeleton/gradlew.bat

@@ -0,0 +1,92 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+
+@if "%DEBUG%"=="" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if %ERRORLEVEL% equ 0 goto execute
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto execute
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %*
+
+:end
+@rem End local scope for the variables with windows NT shell
+if %ERRORLEVEL% equ 0 goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega

kotlin-textfiles-skeleton/src/main/java/textfiles/LazyTextFile.java

@@ -0,0 +1,4 @@
+package textfiles;
+
+class LazyTextFile {
+}

kotlin-textfiles-skeleton/src/main/kotlin/textfiles/FileIndexOutOfBoundsException.kt

@@ -0,0 +1,3 @@
+package textfiles
+
+class FileIndexOutOfBoundsException : IndexOutOfBoundsException()

kotlin-textfiles-skeleton/src/main/kotlin/textfiles/MultiStringTextFile.kt

@@ -0,0 +1,86 @@
+package textfiles
+
+private const val BLOCK_SIZE: Int = 8
+
+class MultiStringTextFile(initialContents: String) : TextFile {
+
+    private var blocks: MutableList<StringBuilder> = mutableListOf(StringBuilder(initialContents))
+
+    /**
+     * Yields the number of blocks that are currently used to represent the file.
+     *
+     * @return The number of blocks used to represent this file.
+     */
+    val numBlocks: Int
+        get() = blocks.size
+
+    override val length: Int
+        get() = TODO("To be implemented.")
+
+    init {
+        rebalance()
+    }
+
+    /**
+     * Reorganises the internal representation of the text file so that the content is partitioned
+     * into blocks of equal size, except that the final block may be shorter.
+     */
+    fun rebalance() {
+        TODO("To be implemented.")
+    }
+
+    override fun insertText(offset: Int, toInsert: String) {
+        TODO("To be implemented.")
+    }
+
+    override fun deleteText(offset: Int, size: Int) {
+        if (offset < 0 || size < 0) {
+            throw FileIndexOutOfBoundsException()
+        }
+        val newBlocks: MutableList<StringBuilder> = mutableListOf()
+        var index = 0
+        var block = 0
+        while (block < blocks.size) {
+            if (index < offset + size && offset < index + blocks[block].length) {
+                if (size == 0) {
+                    return
+                }
+                // Add the prefix
+                val prefixSize: Int = offset - index
+                if (prefixSize > 0) {
+                    newBlocks.add(StringBuilder(blocks[block].substring(0, prefixSize)))
+                }
+                index += prefixSize
+                // If the suffix is in the same block, add it. Otherwise, skip over blocks.
+                if (prefixSize + size < blocks[block].length) {
+                    newBlocks.add(StringBuilder(blocks[block].substring(prefixSize + size)))
+                } else {
+                    var deleted: Int = blocks[block].length - prefixSize
+                    block++
+                    while (block < blocks.size && size - deleted >= blocks[block].length) {
+                        deleted += blocks[block].length
+                        block++
+                    }
+                    if (deleted < size) {
+                        if (block >= blocks.size) {
+                            throw FileIndexOutOfBoundsException()
+                        }
+                        assert(blocks[block].length > size - deleted)
+                        newBlocks.add(StringBuilder(blocks[block].substring(size - deleted)))
+                    }
+                }
+                index += size
+            } else {
+                newBlocks.add(blocks[block])
+                index += blocks[block].length
+            }
+            block++
+        }
+        if (offset >= index) {
+            if (offset > index || size > 0) {
+                throw FileIndexOutOfBoundsException()
+            }
+        }
+        blocks = newBlocks
+    }
+}

kotlin-textfiles-skeleton/src/main/kotlin/textfiles/TextFile.kt

@@ -0,0 +1,30 @@
+package textfiles
+
+interface TextFile {
+    /**
+     * Provides the length of the text file.
+     *
+     * @return the number of characters in the text file
+     */
+    val length: Int
+
+    /**
+     * Inserts text into the file.
+     *
+     * @param offset   The offset at which the text should be inserted
+     * @param toInsert The text to be inserted
+     * @throws FileIndexOutOfBoundsException if offset is negative or larger
+     *  than the length of the file
+     */
+    fun insertText(offset: Int, toInsert: String)
+
+    /**
+     * Deletes text from the file.
+     *
+     * @param offset The offset at which the deletion should occur
+     * @param size   The number of characters to be deleted
+     * @throws FileIndexOutOfBoundsException if offset or size is negative, or
+     *  if offset + size is larger than the length of the file
+     */
+    fun deleteText(offset: Int, size: Int)
+}

kotlin-textfiles-skeleton/src/test/kotlin/textfiles/Question1Tests.kt

@@ -0,0 +1,189 @@
+package textfiles
+
+/*
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.fail
+ */
+
+class Question1Tests {
+/*
+    @Test
+    fun testLength1() {
+        val textFile: TextFile = SingleStringTextFile("")
+        assertEquals(0, textFile.length)
+    }
+
+    @Test
+    fun testLength2() {
+        val textFile: TextFile = SingleStringTextFile("Hello\nWorld")
+        assertEquals(11, textFile.length)
+    }
+
+    @Test
+    fun testInsert1() {
+        val textFile: TextFile = SingleStringTextFile("")
+        textFile.insertText(0, "First")
+        textFile.insertText(0, "Second")
+        textFile.insertText(0, "Third")
+        assertEquals("ThirdSecondFirst", textFile.toString())
+    }
+
+    @Test
+    fun testInsert2() {
+        val textFile: TextFile = SingleStringTextFile("SomeContent")
+        textFile.insertText(11, "MoreContent")
+        textFile.insertText(22, "EvenMoreContent")
+        assertEquals("SomeContentMoreContentEvenMoreContent", textFile.toString())
+    }
+
+    @Test
+    fun testInsert3() {
+        val textFile: TextFile = SingleStringTextFile("SomeContent")
+        textFile.insertText(0, "!")
+        textFile.insertText(2, "!")
+        textFile.insertText(4, "!")
+        textFile.insertText(6, "!")
+        textFile.insertText(8, "!")
+        textFile.insertText(10, "!")
+        textFile.insertText(12, "!")
+        textFile.insertText(14, "!")
+        textFile.insertText(16, "!")
+        textFile.insertText(18, "!")
+        textFile.insertText(20, "!")
+        textFile.insertText(22, "!")
+        assertEquals("!S!o!m!e!C!o!n!t!e!n!t!", textFile.toString())
+    }
+
+    @Test
+    fun testInsertException1() {
+        try {
+            val textFile: TextFile = SingleStringTextFile("SomeContent")
+            textFile.insertText(-1, "DoNotAddMe")
+        } catch (exception: FileIndexOutOfBoundsException) {
+            // Good: an exception should have been thrown.
+            return
+        }
+        fail()
+    }
+
+    @Test
+    fun testInsertException2() {
+        try {
+            val textFile: TextFile = SingleStringTextFile("SomeContent")
+            textFile.insertText(12, "DoNotAddMe")
+        } catch (exception: FileIndexOutOfBoundsException) {
+            // Good: an exception should have been thrown.
+            return
+        }
+        fail()
+    }
+
+    @Test
+    fun testInsertException3() {
+        try {
+            val textFile: TextFile = SingleStringTextFile("SomeContent")
+            textFile.insertText(12, "")
+        } catch (exception: FileIndexOutOfBoundsException) {
+            // Good: an exception should have been thrown.
+            return
+        }
+        fail()
+    }
+
+    @Test
+    fun testDelete1() {
+        val textFile: TextFile = SingleStringTextFile("")
+        textFile.deleteText(0, 0)
+        assertEquals("", textFile.toString())
+    }
+
+    @Test
+    fun testDelete2() {
+        val textFile: TextFile = SingleStringTextFile("Hello")
+        textFile.deleteText(3, 0)
+        assertEquals("Hello", textFile.toString())
+    }
+
+    @Test
+    fun testDelete3() {
+        val textFile: TextFile = SingleStringTextFile("Example text file")
+        textFile.deleteText(0, 17)
+        assertEquals("", textFile.toString())
+    }
+
+    @Test
+    fun testDelete4() {
+        val textFile: TextFile = SingleStringTextFile("Example text file")
+        textFile.deleteText(8, 5)
+        assertEquals("Example file", textFile.toString())
+    }
+
+    @Test
+    fun testDelete5() {
+        val textFile: TextFile = SingleStringTextFile("T")
+        textFile.deleteText(1, 0)
+        assertEquals("T", textFile.toString())
+    }
+
+    @Test
+    fun testDeleteException1() {
+        try {
+            val textFile: TextFile = SingleStringTextFile("SomeContent")
+            textFile.deleteText(-1, 3)
+        } catch (exception: FileIndexOutOfBoundsException) {
+            // Good: an exception should have been thrown.
+            return
+        }
+        fail()
+    }
+
+    @Test
+    fun testDeleteException2() {
+        try {
+            val textFile: TextFile = SingleStringTextFile("SomeContent")
+            textFile.deleteText(0, 12)
+        } catch (exception: FileIndexOutOfBoundsException) {
+            // Good: an exception should have been thrown.
+            return
+        }
+        fail()
+    }
+
+    @Test
+    fun testDeleteException3() {
+        try {
+            val textFile: TextFile = SingleStringTextFile("SomeContent")
+            textFile.deleteText(10, 2)
+        } catch (exception: FileIndexOutOfBoundsException) {
+            // Good: an exception should have been thrown.
+            return
+        }
+        fail()
+    }
+
+    @Test
+    fun testDeleteException4() {
+        try {
+            val textFile: TextFile = SingleStringTextFile("SomeContent")
+            textFile.deleteText(100, 0)
+        } catch (exception: FileIndexOutOfBoundsException) {
+            // Good: an exception should have been thrown.
+            return
+        }
+        fail()
+    }
+
+    @Test
+    fun testDeleteException5() {
+        try {
+            val textFile: TextFile = SingleStringTextFile("SomeContent")
+            textFile.deleteText(0, -1)
+        } catch (exception: FileIndexOutOfBoundsException) {
+            // Good: an exception should have been thrown.
+            return
+        }
+        fail()
+    }
+ */
+}

kotlin-textfiles-skeleton/src/test/kotlin/textfiles/Question2Tests.kt

@@ -0,0 +1,254 @@
+package textfiles
+
+/*
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.fail
+ */
+
+class Question2Tests {
+/*
+    @Test
+    fun testLength1() {
+        val textFile: TextFile = MultiStringTextFile("")
+        assertEquals(0, textFile.length)
+    }
+
+    @Test
+    fun testLength2() {
+        val textFile: TextFile = MultiStringTextFile("Hello\nWorld")
+        assertEquals(11, textFile.length)
+    }
+
+    @Test
+    fun testLength3() {
+        val textFile: TextFile = MultiStringTextFile(
+            "The quick brown fox jumped over the lazy dog ten times today",
+        )
+        assertEquals(60, textFile.length)
+    }
+
+    @Test
+    fun testInsert1() {
+        val textFile: TextFile = MultiStringTextFile("")
+        textFile.insertText(0, "First")
+        textFile.insertText(0, "Second")
+        textFile.insertText(0, "Third")
+        assertEquals("ThirdSecondFirst", textFile.toString())
+    }
+
+    @Test
+    fun testInsert2() {
+        val textFile: TextFile = MultiStringTextFile("SomeContent")
+        textFile.insertText(11, "MoreContent")
+        textFile.insertText(22, "EvenMoreContent")
+        assertEquals("SomeContentMoreContentEvenMoreContent", textFile.toString())
+    }
+
+    @Test
+    fun testInsert3() {
+        val textFile: TextFile = MultiStringTextFile("SomeContent")
+        textFile.insertText(0, "!")
+        textFile.insertText(2, "!")
+        textFile.insertText(4, "!")
+        textFile.insertText(6, "!")
+        textFile.insertText(8, "!")
+        textFile.insertText(10, "!")
+        textFile.insertText(12, "!")
+        textFile.insertText(14, "!")
+        textFile.insertText(16, "!")
+        textFile.insertText(18, "!")
+        textFile.insertText(20, "!")
+        textFile.insertText(22, "!")
+        assertEquals("!S!o!m!e!C!o!n!t!e!n!t!", textFile.toString())
+    }
+
+    @Test
+    fun testInsertException1() {
+        try {
+            val textFile: TextFile = MultiStringTextFile("SomeContent")
+            textFile.insertText(-1, "DoNotAddMe")
+        } catch (exception: FileIndexOutOfBoundsException) {
+            // Good: an exception should have been thrown.
+            return
+        }
+        fail()
+    }
+
+    @Test
+    fun testInsertException2() {
+        try {
+            val textFile: TextFile = MultiStringTextFile("SomeContent")
+            textFile.insertText(12, "DoNotAddMe")
+        } catch (exception: FileIndexOutOfBoundsException) {
+            // Good: an exception should have been thrown.
+            return
+        }
+        fail()
+    }
+
+    @Test
+    fun testInsertException3() {
+        try {
+            val textFile: TextFile = MultiStringTextFile("SomeContent")
+            textFile.insertText(12, "")
+        } catch (exception: FileIndexOutOfBoundsException) {
+            // Good: an exception should have been thrown.
+            return
+        }
+        fail()
+    }
+
+    @Test
+    fun testDelete1() {
+        val textFile: TextFile = MultiStringTextFile("")
+        textFile.deleteText(0, 0)
+        assertEquals("", textFile.toString())
+    }
+
+    @Test
+    fun testDelete2() {
+        val textFile: TextFile = MultiStringTextFile("Hello")
+        textFile.deleteText(3, 0)
+        assertEquals("Hello", textFile.toString())
+    }
+
+    @Test
+    fun testDelete3() {
+        val textFile: TextFile = MultiStringTextFile("Example text file")
+        textFile.deleteText(0, 17)
+        assertEquals("", textFile.toString())
+    }
+
+    @Test
+    fun testDelete4() {
+        val textFile: TextFile = MultiStringTextFile("Example text file")
+        textFile.deleteText(8, 5)
+        assertEquals("Example file", textFile.toString())
+    }
+
+    @Test
+    fun testDelete5() {
+        val textFile: TextFile = MultiStringTextFile("T")
+        textFile.deleteText(1, 0)
+        assertEquals("T", textFile.toString())
+    }
+
+    @Test
+    fun testDelete6() {
+        val textFile: TextFile = MultiStringTextFile(
+            "The quick brown fox jumped over the lazy dog ten times today",
+        )
+        textFile.deleteText(3, 43)
+        assertEquals("Theen times today", textFile.toString())
+    }
+
+    @Test
+    fun testDeleteException1() {
+        try {
+            val textFile: TextFile = MultiStringTextFile("SomeContent")
+            textFile.deleteText(-1, 3)
+        } catch (exception: FileIndexOutOfBoundsException) {
+            // Good: an exception should have been thrown.
+            return
+        }
+        fail()
+    }
+
+    @Test
+    fun testDeleteException2() {
+        try {
+            val textFile: TextFile = MultiStringTextFile("SomeContent")
+            textFile.deleteText(0, 12)
+        } catch (exception: FileIndexOutOfBoundsException) {
+            // Good: an exception should have been thrown.
+            return
+        }
+        fail()
+    }
+
+    @Test
+    fun testDeleteException3() {
+        try {
+            val textFile: TextFile = MultiStringTextFile("SomeContent")
+            textFile.deleteText(10, 2)
+        } catch (exception: FileIndexOutOfBoundsException) {
+            // Good: an exception should have been thrown.
+            return
+        }
+        fail()
+    }
+
+    @Test
+    fun testDeleteException4() {
+        try {
+            val textFile: TextFile = MultiStringTextFile("SomeContent")
+            textFile.deleteText(100, 0)
+        } catch (exception: FileIndexOutOfBoundsException) {
+            // Good: an exception should have been thrown.
+            return
+        }
+        fail()
+    }
+
+    @Test
+    fun testDeleteException5() {
+        try {
+            val textFile: TextFile = MultiStringTextFile("SomeContent")
+            textFile.deleteText(0, -1)
+        } catch (exception: FileIndexOutOfBoundsException) {
+            // Good: an exception should have been thrown.
+            return
+        }
+        fail()
+    }
+
+    @Test
+    fun testGetNumBlocksAndRebalance1() {
+        val textFile = MultiStringTextFile("")
+        assertEquals(0, textFile.numBlocks)
+        textFile.rebalance()
+        assertEquals(0, textFile.numBlocks)
+    }
+
+    @Test
+    fun testGetNumBlocksAndRebalance2() {
+        val textFile = MultiStringTextFile(
+            "AKAI Professional MPK249 midi controller does not act as a stand-alone synthesizer, unfortunately.",
+        )
+        assertEquals(13, textFile.numBlocks)
+        textFile.rebalance()
+        assertEquals(13, textFile.numBlocks)
+    }
+
+    @Test
+    fun testGetNumBlocksAndRebalance3() {
+        val textFile = MultiStringTextFile("Harmonious")
+        assertEquals(2, textFile.numBlocks)
+        textFile.rebalance()
+        assertEquals(2, textFile.numBlocks)
+        textFile.insertText(2, "A")
+        assertEquals(2, textFile.numBlocks)
+        textFile.insertText(11, "B")
+        assertEquals(3, textFile.numBlocks)
+        textFile.insertText(12, "C")
+        assertEquals(4, textFile.numBlocks)
+        textFile.rebalance()
+        assertEquals(2, textFile.numBlocks)
+        assertEquals("HaArmoniousBC", textFile.toString())
+    }
+
+    @Test
+    fun testGetNumBlocksAndRebalance4() {
+        val textFile = MultiStringTextFile("Harmonious")
+        assertEquals(2, textFile.numBlocks)
+        textFile.rebalance()
+        assertEquals(2, textFile.numBlocks)
+        textFile.deleteText(2, 1)
+        assertEquals(3, textFile.numBlocks)
+        textFile.deleteText(7, 2)
+        assertEquals(2, textFile.numBlocks)
+        assertEquals("Hamonio", textFile.toString())
+    }
+ */
+}

kotlin-textfiles-skeleton/src/test/kotlin/textfiles/Question3Tests.kt

@@ -0,0 +1,295 @@
+package textfiles
+
+/*
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.fail
+ */
+
+class Question3Tests {
+
+/*
+    @Test
+    fun testLength1() {
+        val textFile: TextFile = LazyTextFile(SingleStringTextFile(""))
+        assertEquals(0, textFile.length)
+    }
+
+    @Test
+    fun testLength2() {
+        val textFile: TextFile = LazyTextFile(SingleStringTextFile("Hello\nWorld"))
+        assertEquals(11, textFile.length)
+    }
+
+    @Test
+    fun testLength3() {
+        val textFile: TextFile = LazyTextFile(
+            SingleStringTextFile(
+                "The quick brown fox jumped over the lazy dog ten times today",
+            ),
+        )
+        assertEquals(60, textFile.length)
+    }
+
+    @Test
+    fun testInsert1() {
+        val textFile: TextFile = LazyTextFile(SingleStringTextFile(""))
+        textFile.insertText(0, "First")
+        textFile.insertText(0, "Second")
+        textFile.insertText(0, "Third")
+        assertEquals("ThirdSecondFirst", textFile.toString())
+    }
+
+    @Test
+    fun testInsert2() {
+        val textFile: TextFile = LazyTextFile(SingleStringTextFile("SomeContent"))
+        textFile.insertText(11, "MoreContent")
+        textFile.insertText(22, "EvenMoreContent")
+        assertEquals("SomeContentMoreContentEvenMoreContent", textFile.toString())
+    }
+
+    @Test
+    fun testInsert3() {
+        val textFile: TextFile = LazyTextFile(SingleStringTextFile("SomeContent"))
+        textFile.insertText(0, "!")
+        textFile.insertText(2, "!")
+        textFile.insertText(4, "!")
+        textFile.insertText(6, "!")
+        textFile.insertText(8, "!")
+        textFile.insertText(10, "!")
+        textFile.insertText(12, "!")
+        textFile.insertText(14, "!")
+        textFile.insertText(16, "!")
+        textFile.insertText(18, "!")
+        textFile.insertText(20, "!")
+        textFile.insertText(22, "!")
+        assertEquals("!S!o!m!e!C!o!n!t!e!n!t!", textFile.toString())
+    }
+
+    @Test
+    fun testInsertException1() {
+        try {
+            val textFile: TextFile = LazyTextFile(SingleStringTextFile("SomeContent"))
+            textFile.insertText(-1, "DoNotAddMe")
+            textFile.insertText(0, "a")
+        } catch (exception: FileIndexOutOfBoundsException) {
+            // Good: an exception should have been thrown.
+            return
+        }
+        fail()
+    }
+
+    @Test
+    fun testInsertException2() {
+        try {
+            val textFile: TextFile = LazyTextFile(SingleStringTextFile("SomeContent"))
+            textFile.insertText(12, "DoNotAddMe")
+            textFile.insertText(0, "a")
+        } catch (exception: FileIndexOutOfBoundsException) {
+            // Good: an exception should have been thrown.
+            return
+        }
+        fail()
+    }
+
+    @Test
+    fun testInsertException3() {
+        try {
+            val textFile: TextFile = LazyTextFile(SingleStringTextFile("SomeContent"))
+            textFile.insertText(12, "")
+            textFile.insertText(0, "a")
+        } catch (exception: FileIndexOutOfBoundsException) {
+            // Good: an exception should have been thrown.
+            return
+        }
+        fail()
+    }
+
+    @Test
+    fun testDelete1() {
+        val textFile: TextFile = LazyTextFile(SingleStringTextFile(""))
+        textFile.deleteText(0, 0)
+        assertEquals("", textFile.toString())
+    }
+
+    @Test
+    fun testDelete2() {
+        val textFile: TextFile = LazyTextFile(SingleStringTextFile("Hello"))
+        textFile.deleteText(3, 0)
+        assertEquals("Hello", textFile.toString())
+    }
+
+    @Test
+    fun testDelete3() {
+        val textFile: TextFile = LazyTextFile(SingleStringTextFile("Example text file"))
+        textFile.deleteText(0, 17)
+        assertEquals("", textFile.toString())
+    }
+
+    @Test
+    fun testDelete4() {
+        val textFile: TextFile = LazyTextFile(SingleStringTextFile("Example text file"))
+        textFile.deleteText(8, 5)
+        assertEquals("Example file", textFile.toString())
+    }
+
+    @Test
+    fun testDelete5() {
+        val textFile: TextFile = LazyTextFile(SingleStringTextFile("T"))
+        textFile.deleteText(1, 0)
+        assertEquals("T", textFile.toString())
+    }
+
+    @Test
+    fun testDelete6() {
+        val textFile: TextFile = LazyTextFile(
+            SingleStringTextFile(
+                "The quick brown fox jumped over the lazy dog ten times today",
+            ),
+        )
+        textFile.deleteText(3, 43)
+        assertEquals("Theen times today", textFile.toString())
+    }
+
+    @Test
+    fun testDeleteException1() {
+        try {
+            val textFile: TextFile = LazyTextFile(SingleStringTextFile("SomeContent"))
+            textFile.deleteText(-1, 3)
+        } catch (exception: FileIndexOutOfBoundsException) {
+            // Good: an exception should have been thrown.
+            return
+        }
+        fail()
+    }
+
+    @Test
+    fun testDeleteException2() {
+        try {
+            val textFile: TextFile = LazyTextFile(SingleStringTextFile("SomeContent"))
+            textFile.deleteText(0, 12)
+        } catch (exception: FileIndexOutOfBoundsException) {
+            // Good: an exception should have been thrown.
+            return
+        }
+        fail()
+    }
+
+    @Test
+    fun testDeleteException3() {
+        try {
+            val textFile: TextFile = LazyTextFile(SingleStringTextFile("SomeContent"))
+            textFile.deleteText(10, 2)
+        } catch (exception: FileIndexOutOfBoundsException) {
+            // Good: an exception should have been thrown.
+            return
+        }
+        fail()
+    }
+
+    @Test
+    fun testDeleteException4() {
+        try {
+            val textFile: TextFile = LazyTextFile(SingleStringTextFile("SomeContent"))
+            textFile.deleteText(100, 0)
+        } catch (exception: FileIndexOutOfBoundsException) {
+            // Good: an exception should have been thrown.
+            return
+        }
+        fail()
+    }
+
+    @Test
+    fun testDeleteException5() {
+        try {
+            val textFile: TextFile = LazyTextFile(SingleStringTextFile("SomeContent"))
+            textFile.deleteText(0, -1)
+        } catch (exception: FileIndexOutOfBoundsException) {
+            // Good: an exception should have been thrown.
+            return
+        }
+        fail()
+    }
+
+    @Test
+    fun testLaziness() {
+        val operationCountingTextFile = OperationCountingTextFile()
+        val lazyTextFile: TextFile = LazyTextFile(operationCountingTextFile)
+        assertEquals(0, operationCountingTextFile.numInsertions)
+        assertEquals(0, operationCountingTextFile.numDeletions)
+
+        lazyTextFile.insertText(0, "hello")
+        assertEquals(0, operationCountingTextFile.numInsertions)
+        assertEquals(0, operationCountingTextFile.numDeletions)
+
+        lazyTextFile.insertText(0, "hello")
+        assertEquals(0, operationCountingTextFile.numInsertions)
+        assertEquals(0, operationCountingTextFile.numDeletions)
+
+        lazyTextFile.insertText(0, "hello")
+        assertEquals(0, operationCountingTextFile.numInsertions)
+        assertEquals(0, operationCountingTextFile.numDeletions)
+
+        lazyTextFile.length
+        assertEquals(1, operationCountingTextFile.numInsertions)
+        assertEquals(0, operationCountingTextFile.numDeletions)
+
+        lazyTextFile.insertText(0, "hello")
+        assertEquals(1, operationCountingTextFile.numInsertions)
+        assertEquals(0, operationCountingTextFile.numDeletions)
+
+        lazyTextFile.deleteText(5, 2)
+        assertEquals(2, operationCountingTextFile.numInsertions)
+        assertEquals(1, operationCountingTextFile.numDeletions)
+
+        lazyTextFile.insertText(0, "hello")
+        assertEquals(2, operationCountingTextFile.numInsertions)
+        assertEquals(1, operationCountingTextFile.numDeletions)
+
+        lazyTextFile.insertText(0, "hello")
+        assertEquals(2, operationCountingTextFile.numInsertions)
+        assertEquals(1, operationCountingTextFile.numDeletions)
+
+        //noinspection ResultOfMethodCallIgnored
+        lazyTextFile.toString()
+        assertEquals(3, operationCountingTextFile.numInsertions)
+        assertEquals(1, operationCountingTextFile.numDeletions)
+
+        lazyTextFile.insertText(0, "hello")
+        assertEquals(3, operationCountingTextFile.numInsertions)
+        assertEquals(1, operationCountingTextFile.numDeletions)
+
+        lazyTextFile.insertText(1, "hello")
+        assertEquals(4, operationCountingTextFile.numInsertions)
+        assertEquals(1, operationCountingTextFile.numDeletions)
+
+        lazyTextFile.insertText(1, "hello")
+        assertEquals(4, operationCountingTextFile.numInsertions)
+        assertEquals(1, operationCountingTextFile.numDeletions)
+
+        lazyTextFile.deleteText(1, 6)
+        assertEquals(5, operationCountingTextFile.numInsertions)
+        assertEquals(2, operationCountingTextFile.numDeletions)
+    }
+
+    class OperationCountingTextFile : TextFile {
+
+        var numInsertions = 0
+            private set
+
+        var numDeletions = 0
+            private set
+
+        override val length: Int
+            get() = 1000
+
+        override fun insertText(offset: Int, toInsert: String) {
+            numInsertions++
+        }
+
+        override fun deleteText(offset: Int, size: Int) {
+            numDeletions++
+        }
+    }
+ */
+}

kotlin-textfiles-skeleton/src/test/kotlin/textfiles/Question4Tests.kt

@@ -0,0 +1,36 @@
+package textfiles
+
+/*
+import java.util.Random
+import kotlin.test.Test
+import kotlin.test.assertEquals
+ */
+
+class Question4Tests {
+/*
+    @Test
+    fun concurrencyTest() {
+        for (repeat in 1..20) {
+            println("Repeat run $repeat")
+            val initialText = "initialtext"
+            val authorStrings: List<List<String>> = (0..<8).map {
+                (0..<1000).map {
+                    (0..it % 10).map { number -> number.toString() }.joinToString(separator = "")
+                }
+            }
+            val expectedOutput: String =
+                (initialText + authorStrings.flatten().joinToString(separator = ""))
+                    .toCharArray().sortedArray().joinToString(separator = "")
+
+            val singleStringTextFile = SingleStringTextFile(initialText)
+
+            // TODO - complete this test
+
+            assertEquals(
+                expectedOutput,
+                threadSafeTextFile.toString().toCharArray().sortedArray().joinToString(separator = ""),
+            )
+        }
+    }
+ */
+}

kotlin-textfiles-skeleton/src/test/kotlin/textfiles/Question5Tests.kt

@@ -0,0 +1,59 @@
+package textfiles
+
+/*
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertTrue
+ */
+
+class Question5Tests {
+/*
+    @Test
+    fun testCompareTo1() {
+        val t1: TextFile = SingleStringTextFile("Hello")
+        val t2: TextFile = SingleStringTextFile("Hello")
+        assertEquals(0, t1.compareTo(t2))
+        assertEquals(0, t2.compareTo(t1))
+    }
+
+    @Test
+    fun testCompareTo2() {
+        val t1: TextFile = SingleStringTextFile("Hell")
+        val t2: TextFile = SingleStringTextFile("Hello")
+        assertTrue(t1 < t2)
+        assertTrue(t2 > t1)
+    }
+
+    @Test
+    fun testCompareTo3() {
+        val t1: TextFile = MultiStringTextFile("Hello")
+        val t2: TextFile = SingleStringTextFile("Hello")
+        assertEquals(0, t1.compareTo(t2))
+        assertEquals(0, t2.compareTo(t1))
+    }
+
+    @Test
+    fun testCompareTo4() {
+        val t1: TextFile = MultiStringTextFile("Aello")
+        val t2: TextFile = SingleStringTextFile("Hello")
+        assertTrue(t1 < t2)
+        assertTrue(t2 > t1)
+    }
+
+    @Test
+    fun testCompareTo5() {
+        val t1: TextFile = MultiStringTextFile("Hello")
+        val t2: TextFile = MultiStringTextFile("Hello")
+        assertEquals(0, t1.compareTo(t2))
+        assertEquals(0, t2.compareTo(t1))
+    }
+
+    @Test
+    fun testCompareTo6() {
+        val t1: TextFile = MultiStringTextFile("Hella")
+        val t2: TextFile = MultiStringTextFile("Hello")
+        assertTrue(t1 < t2)
+        assertTrue(t2 > t1)
+    }
+ */
+}

kotlin-textfiles-skeleton/src/test/kotlin/textfiles/Question6Tests.kt

@@ -0,0 +1,198 @@
+package textfiles
+
+/*
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertNull
+import kotlin.test.assertSame
+ */
+
+class Question6Tests {
+/*
+    private val file1: TextFile = SingleStringTextFile("File1Contents")
+    private val file2: TextFile = SingleStringTextFile("File2Contents")
+    private val file3: TextFile = SingleStringTextFile("File3Contents")
+    private val file4: TextFile = SingleStringTextFile("File4Contents")
+    private val file5: TextFile = SingleStringTextFile("File5Contents")
+
+    @Test
+    fun testGetSetAndSize() {
+        val fileMap = FileMap()
+        assertEquals(0, fileMap.size)
+        assertNull(fileMap.get("a"))
+        assertNull(fileMap.get("b"))
+        assertNull(fileMap.get("c"))
+        assertNull(fileMap.get("d"))
+        assertNull(fileMap.get("e"))
+
+        fileMap.set("a", file1)
+        assertEquals(1, fileMap.size)
+        assertSame(file1, fileMap.get("a"))
+        assertNull(fileMap.get("b"))
+        assertNull(fileMap.get("c"))
+        assertNull(fileMap.get("d"))
+        assertNull(fileMap.get("e"))
+
+        fileMap.set("b", file2)
+        assertEquals(2, fileMap.size)
+        assertSame(file1, fileMap.get("a"))
+        assertSame(file2, fileMap.get("b"))
+        assertNull(fileMap.get("c"))
+        assertNull(fileMap.get("d"))
+        assertNull(fileMap.get("e"))
+
+        fileMap.set("c", file3)
+        assertEquals(3, fileMap.size)
+        assertSame(file1, fileMap.get("a"))
+        assertSame(file2, fileMap.get("b"))
+        assertSame(file3, fileMap.get("c"))
+        assertNull(fileMap.get("d"))
+        assertNull(fileMap.get("e"))
+
+        fileMap.set("d", file4)
+        assertEquals(4, fileMap.size)
+        assertSame(file1, fileMap.get("a"))
+        assertSame(file2, fileMap.get("b"))
+        assertSame(file3, fileMap.get("c"))
+        assertSame(file4, fileMap.get("d"))
+        assertNull(fileMap.get("e"))
+
+        fileMap.set("e", file5)
+        assertEquals(5, fileMap.size)
+        assertSame(file1, fileMap.get("a"))
+        assertSame(file2, fileMap.get("b"))
+        assertSame(file3, fileMap.get("c"))
+        assertSame(file4, fileMap.get("d"))
+        assertSame(file5, fileMap.get("e"))
+
+        fileMap.set("a", file2)
+        fileMap.set("b", file3)
+        fileMap.set("c", file4)
+        fileMap.set("d", file5)
+        fileMap.set("e", file1)
+
+        assertSame(file2, fileMap.get("a"))
+        assertSame(file3, fileMap.get("b"))
+        assertSame(file4, fileMap.get("c"))
+        assertSame(file5, fileMap.get("d"))
+        assertSame(file1, fileMap.get("e"))
+    }
+
+    @Test
+    fun testGetSetAndSizeViaOperator() {
+        val fileMap = FileMap()
+        assertEquals(0, fileMap.size)
+        assertNull(fileMap["a"])
+        assertNull(fileMap["b"])
+        assertNull(fileMap["c"])
+        assertNull(fileMap["d"])
+        assertNull(fileMap["e"])
+
+        fileMap["a"] = file1
+        assertEquals(1, fileMap.size)
+        assertSame(file1, fileMap["a"])
+        assertNull(fileMap["b"])
+        assertNull(fileMap["c"])
+        assertNull(fileMap["d"])
+        assertNull(fileMap["e"])
+
+        fileMap["b"] = file2
+        assertEquals(2, fileMap.size)
+        assertSame(file1, fileMap["a"])
+        assertSame(file2, fileMap["b"])
+        assertNull(fileMap["c"])
+        assertNull(fileMap["d"])
+        assertNull(fileMap["e"])
+
+        fileMap["c"] = file3
+        assertEquals(3, fileMap.size)
+        assertSame(file1, fileMap["a"])
+        assertSame(file2, fileMap["b"])
+        assertSame(file3, fileMap["c"])
+        assertNull(fileMap["d"])
+        assertNull(fileMap["e"])
+
+        fileMap["d"] = file4
+        assertEquals(4, fileMap.size)
+        assertSame(file1, fileMap["a"])
+        assertSame(file2, fileMap["b"])
+        assertSame(file3, fileMap["c"])
+        assertSame(file4, fileMap["d"])
+        assertNull(fileMap["e"])
+
+        fileMap["e"] = file5
+        assertEquals(5, fileMap.size)
+        assertSame(file1, fileMap["a"])
+        assertSame(file2, fileMap["b"])
+        assertSame(file3, fileMap["c"])
+        assertSame(file4, fileMap["d"])
+        assertSame(file5, fileMap["e"])
+
+        fileMap["a"] = file2
+        fileMap["b"] = file3
+        fileMap["c"] = file4
+        fileMap["d"] = file5
+        fileMap["e"] = file1
+
+        assertSame(file2, fileMap["a"])
+        assertSame(file3, fileMap["b"])
+        assertSame(file4, fileMap["c"])
+        assertSame(file5, fileMap["d"])
+        assertSame(file1, fileMap["e"])
+    }
+
+    @Test
+    fun testIterator() {
+        val fileMap = FileMap()
+        val files: Array<TextFile> = Array(100) { SingleStringTextFile(it.toString()) }
+        for (i in 0..<100) {
+            fileMap.set("$i".padStart(2, '0'), files[i])
+        }
+        val iterator = fileMap.iterator()
+        val retrievedContents: MutableList<Pair<String, TextFile>> = mutableListOf()
+        while (iterator.hasNext()) {
+            retrievedContents.add(iterator.next())
+        }
+        assertEquals(100, retrievedContents.size)
+        val retrievedContentsSorted = retrievedContents.sortedBy { it.first }
+        for (i in 0..<100) {
+            assertEquals("$i".padStart(2, '0'), retrievedContentsSorted[i].first)
+            assertSame(files[i], retrievedContentsSorted[i].second)
+        }
+    }
+
+    @Test
+    fun testIteratorViaOperator() {
+        val fileMap = FileMap()
+        val files: Array<TextFile> = Array(100) { SingleStringTextFile(it.toString()) }
+        for (i in 0..<100) {
+            fileMap.set("$i".padStart(2, '0'), files[i])
+        }
+        val retrievedContents: MutableList<Pair<String, TextFile>> = mutableListOf()
+        for (entry in fileMap) {
+            retrievedContents.add(entry)
+        }
+        assertEquals(100, retrievedContents.size)
+        val retrievedContentsSorted = retrievedContents.sortedBy { it.first }
+        for (i in 0..<100) {
+            assertEquals("$i".padStart(2, '0'), retrievedContentsSorted[i].first)
+            assertSame(files[i], retrievedContentsSorted[i].second)
+        }
+    }
+
+    @Test
+    fun performanceTest() {
+        val numElements = 1000000
+        val fileMap: FileMap = FileMap()
+        val files: Array<TextFile> = Array(numElements) { SingleStringTextFile(it.toString()) }
+        (0..<numElements).forEach {
+            assertEquals(it, fileMap.size)
+            fileMap.set("f$it", files[it])
+        }
+        assertEquals(numElements, fileMap.size)
+        for (i in 0..<numElements) {
+            assertSame(files[i], fileMap.get("f$i"))
+        }
+    }
+ */
+}