Lint and test job

.github/workflows/main.yaml

@@ -7,3 +7,23 @@ on:
     branches:
       - main
 jobs:
+  lint-and-test:
+    name: Lint and test library
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Java
+        uses: actions/setup-java@v3
+        with:
+          distribution: 'adopt'
+          java-version: 17
+
+      - name: Verify Gradle wrapper
+        uses: gradle/wrapper-validation-action@v1
+
+      - name: Setup Gradle
+        uses: gradle/gradle-build-action@v2
+
+      - name: Run checks
+        run: ./gradlew check

.idea/gradle.xml

@@ -5,6 +5,7 @@
     <option name="linkedExternalProjectsSettings">
       <GradleProjectSettings>
         <option name="externalProjectPath" value="$PROJECT_DIR$" />
+        <option name="gradleJvm" value="corretto-19" />
         <option name="modules">
           <set>
             <option value="$PROJECT_DIR$" />

src/main/kotlin/tinyvm/Commit.kt

@@ -7,17 +7,19 @@ abstract class Object(
     val type: String,
 ) {
     abstract val data: String
-    fun hash(): String = MessageDigest
+
-        .getInstance("SHA-1")
+    fun hash(): String =
-        .digest("$type ${data.length}\u0000$data".toByteArray())
+        MessageDigest
-        .toHex()
+            .getInstance("SHA-1")
+            .digest("$type ${data.length}\u0000$data".toByteArray())
+            .toHex()
 }
 
 class Commit(
     val tree: Tree,
     val author: Author,
     val message: String,
-    val timestamp: Instant
+    val timestamp: Instant,
 ) : Object("commit") {
     // Use \n\n for end of header in-case additional metadata is implemented in the future.
     override val data: String
@@ -26,8 +28,7 @@ class Commit(
 
 data class Author(
     val name: String,
-    val email: String
+    val email: String,
 ) {
-    override fun toString(): String =
+    override fun toString(): String = "$name <$email>"
-        "$name <$email>"
 }

src/main/kotlin/tinyvm/Extensions.kt

@@ -2,5 +2,4 @@ package tinyvm
 
 import java.util.HexFormat
 
-fun ByteArray.toHex(): String =
+fun ByteArray.toHex(): String = HexFormat.of().formatHex(this)
-     HexFormat.of().formatHex(this)

src/main/kotlin/tinyvm/Repository.kt

@@ -2,9 +2,11 @@ package tinyvm
 
 class HashCollisionException(hash: String) : Exception("Different object types with identical hash '$hash'")
 
-class CommitTimeComparator: Comparator<Commit> {
+class CommitTimeComparator : Comparator<Commit> {
-    override fun compare(o1: Commit, o2: Commit): Int =
+    override fun compare(
-        (o1.timestamp.epochSecond - o2.timestamp.epochSecond).toInt()
+        o1: Commit,
+        o2: Commit,
+    ): Int = (o1.timestamp.epochSecond - o2.timestamp.epochSecond).toInt()
 }
 
 class Repository {
@@ -23,12 +25,13 @@ class Repository {
         val hash = commit.hash()
         val obj = findObject<Commit>(hash)
         if (obj != null) return obj
-        val newCommit = Commit(
+        val newCommit =
-            tree = addTree(commit.tree),
+            Commit(
-            author = commit.author,
+                tree = addTree(commit.tree),
-            message = commit.message,
+                author = commit.author,
-            timestamp = commit.timestamp
+                message = commit.message,
-        )
+                timestamp = commit.timestamp,
+            )
         objects[hash] = newCommit
         commits.add(newCommit)
         return newCommit
@@ -47,8 +50,7 @@ class Repository {
     /**
      * Find commit.
      */
-    fun findCommit(predicate: (Commit) -> Boolean): Commit? =
+    fun findCommit(predicate: (Commit) -> Boolean): Commit? = commits.find(predicate)
-        commits.find(predicate)
 
     /**
      * Dump repository objects
@@ -63,14 +65,15 @@ class Repository {
         val hash = tree.hash()
         val obj = findObject<Tree>(hash)
         if (obj != null) return obj
-        val newTree = Tree(
+        val newTree =
-            tree.nodes.map { (name, node) ->
+            Tree(
-                when (node) {
+                tree.nodes.map { (name, node) ->
-                    is Tree -> name to addTree(node)
+                    when (node) {
-                    is Blob -> name to addObject(node)
+                        is Tree -> name to addTree(node)
-                }
+                        is Blob -> name to addObject(node)
-            }.toMap()
+                    }
-        )
+                }.toMap(),
+            )
         objects[hash] = newTree
         return tree
     }
@@ -86,5 +89,4 @@ class Repository {
      */
     private inline fun <reified T : Object> findObject(hash: String): T? =
         objects[hash]?.let { it as? T ?: throw HashCollisionException(hash) }
-
 }

src/main/kotlin/tinyvm/Tree.kt

@@ -1,13 +1,14 @@
 package tinyvm
 
-sealed class Node(type: String): Object(type)
+sealed class Node(type: String) : Object(type)
 
 class Tree(val nodes: Map<String, Node>) : Node("tree") {
     // For simplicity just use the hex-formatted hash, not the actual value like git does.
     override val data: String
-        get() = nodes.map { (name, node) ->
+        get() =
-            "${node.type} $name\u0000${node.hash()}"
+            nodes.map { (name, node) ->
-        }.sorted().joinToString()
+                "${node.type} $name\u0000${node.hash()}"
+            }.sorted().joinToString()
 }
 
 class Blob(override val data: String) : Node("blob")

src/test/kotlin/tinyvm/RepositoryTest.kt

@@ -6,51 +6,60 @@ import kotlin.test.assertEquals
 
 internal class RepositoryTest {
     private val repository = Repository()
-    private val commits = listOf(
+    private val commits =
-        Commit(
+        listOf(
-            tree = Tree(mapOf("test1.txt" to Blob("Hello World!"))),
+            Commit(
-            author = Author("Gleb Koval", "gleb@koval.net"),
+                tree = Tree(mapOf("test1.txt" to Blob("Hello World!"))),
-            message = "Add test1.txt",
+                author = Author("Gleb Koval", "gleb@koval.net"),
-            timestamp = Instant.ofEpochSecond(0)
+                message = "Add test1.txt",
-        ), Commit(
+                timestamp = Instant.ofEpochSecond(0),
-            tree = Tree(
-                mapOf(
-                    "dir1" to Tree(
-                        mapOf(
-                            "test1.txt" to Blob("Hello World!")
-                        )
-                    ),
-                    "dir2" to Tree(
-                        mapOf(
-                            "test2.txt" to Blob("This is a second file")
-                        )
-                    )
-                )
             ),
-            author = Author("Gleb Koval", "gleb@koval.net"),
+            Commit(
-            message = "Move test1.txt and add dir2/test2.txt",
+                tree =
-            timestamp = Instant.ofEpochSecond(50)
+                    Tree(
-        ), Commit(
-            tree = Tree(
-                mapOf(
-                    "dir1" to Tree(
                         mapOf(
-                            "test1.txt" to Blob("Hello World!")
+                            "dir1" to
-                        )
+                                Tree(
+                                    mapOf(
+                                        "test1.txt" to Blob("Hello World!"),
+                                    ),
+                                ),
+                            "dir2" to
+                                Tree(
+                                    mapOf(
+                                        "test2.txt" to Blob("This is a second file"),
+                                    ),
+                                ),
+                        ),
                     ),
-                    "dir2" to Tree(
+                author = Author("Gleb Koval", "gleb@koval.net"),
-                        mapOf(
+                message = "Move test1.txt and add dir2/test2.txt",
-                            "test2.txt" to Blob("This is a second file")
+                timestamp = Instant.ofEpochSecond(50),
-                        )
+            ),
-                    ),
+            Commit(
-                    "README.md" to Blob("# This is a test repo!")
+                tree =
-                )
+                    Tree(
+                        mapOf(
+                            "dir1" to
+                                Tree(
+                                    mapOf(
+                                        "test1.txt" to Blob("Hello World!"),
+                                    ),
+                                ),
+                            "dir2" to
+                                Tree(
+                                    mapOf(
+                                        "test2.txt" to Blob("This is a second file"),
+                                    ),
+                                ),
+                            "README.md" to Blob("# This is a test repo!"),
+                        ),
+                    ),
+                author = Author("Gleb Koval", "gleb@koval.net"),
+                message = "Add README.md",
+                timestamp = Instant.ofEpochSecond(100),
             ),
-            author = Author("Gleb Koval", "gleb@koval.net"),
-            message = "Add README.md",
-            timestamp = Instant.ofEpochSecond(100)
         )
-    )
 
     @Test
     fun `can commit`() {