Add support for JUnit 4 via junit-vintage

selfie-runner-junit5/src/main/kotlin/com/diffplug/selfie/junit5/SelfieGC.kt

@@ -22,6 +22,20 @@ import java.nio.file.Files
 import kotlin.io.path.name
 import org.junit.jupiter.api.Test
 
+/** Search for any test annotation classes which are present on the classpath. */
+private val testAnnotations =
+    listOf(
+            "org.junit.jupiter.api.Test", // junit5,
+            "org.junit.Test" // junit4
+            )
+        .mapNotNull {
+          try {
+            Class.forName(it).asSubclass(Annotation::class.java)
+          } catch (e: ClassNotFoundException) {
+            null
+          }
+        }
+
 /**
  * Searches the whole snapshot directory, finds all the `.ss` files, and prunes any which don't have
  * matching test files anymore.
@@ -41,7 +55,9 @@ internal fun findStaleSnapshotFiles(layout: SnapshotFileLayout): List<String> {
 }
 private fun classExistsAndHasTests(key: String): Boolean {
   return try {
-    Class.forName(key).declaredMethods.any { it.isAnnotationPresent(Test::class.java) }
+    Class.forName(key).methods.any { method ->
+      testAnnotations.any { method.isAnnotationPresent(it) }
+    }
   } catch (e: ClassNotFoundException) {
     false
   }

selfie-runner-junit5/src/main/kotlin/com/diffplug/selfie/junit5/SelfieTestExecutionListener.kt

@@ -21,6 +21,8 @@ import com.diffplug.selfie.RW
 import java.nio.charset.StandardCharsets
 import java.nio.file.Files
 import java.nio.file.Path
+import java.util.concurrent.ConcurrentSkipListSet
+import java.util.concurrent.atomic.AtomicReference
 import org.junit.platform.engine.TestExecutionResult
 import org.junit.platform.engine.support.descriptor.ClassSource
 import org.junit.platform.engine.support.descriptor.MethodSource
@@ -121,6 +123,7 @@ internal class ClassProgress(val parent: Progress, val className: String) {
         if (file!!.snapshots.isEmpty()) {
           deleteFileAndParentDirIfEmpty(snapshotPath)
         } else {
+          parent.markPathAsWritten(parent.layout.snapshotPathForClass(className))
           Files.createDirectories(snapshotPath.parent)
           Files.newBufferedWriter(snapshotPath, StandardCharsets.UTF_8).use { writer ->
             file!!.serialize(writer::write)
@@ -227,10 +230,27 @@ internal class Progress {
       }
     }
   }
+
+  private var checkForInvalidStale: AtomicReference<MutableSet<Path>?> =
+      AtomicReference(ConcurrentSkipListSet())
+  internal fun markPathAsWritten(path: Path) {
+    val written =
+        checkForInvalidStale.get()
+            ?: throw AssertionError("Snapshot file is being written after all tests were finished.")
+    written.add(path)
+  }
   fun finishedAllTests() {
+    val written =
+        checkForInvalidStale.getAndSet(null)
+            ?: throw AssertionError("finishedAllTests() was called more than once.")
     for (stale in findStaleSnapshotFiles(layout)) {
       val path = layout.snapshotPathForClass(stale)
-      deleteFileAndParentDirIfEmpty(path)
+      if (written.contains(path)) {
+        throw AssertionError(
+            "Selfie wrote a snapshot and then marked it stale for deletion it in the same run: $path\nSelfie will delete this snapshot on the next run, which is bad! Why is Selfie marking this snapshot as stale?")
+      } else {
+        deleteFileAndParentDirIfEmpty(path)
+      }
     }
   }
 }

selfie-runner-junit5/src/test/kotlin/com/diffplug/selfie/junitvintage/ReadWriteVintageTest.kt

@@ -0,0 +1,85 @@
+/*
+ * Copyright (C) 2023 DiffPlug
+ *
+ * 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.
+ */
+package com.diffplug.selfie.junitvintage
+
+import com.diffplug.selfie.junit5.Harness
+import kotlin.test.Test
+import org.junit.jupiter.api.MethodOrderer
+import org.junit.jupiter.api.Order
+import org.junit.jupiter.api.TestMethodOrder
+import org.junitpioneer.jupiter.DisableIfTestFails
+
+/** Simplest test for verifying read/write of a snapshot. */
+@TestMethodOrder(MethodOrderer.OrderAnnotation::class)
+@DisableIfTestFails
+class ReadWriteVintageTest : Harness("undertest-junit-vintage") {
+  @Test @Order(1)
+  fun noSelfie() {
+    ut_snapshot().deleteIfExists()
+    ut_snapshot().assertDoesNotExist()
+  }
+
+  @Test @Order(2)
+  fun writeApple() {
+    ut_mirror().lineWith("apple").uncomment()
+    ut_mirror().lineWith("orange").commentOut()
+    gradleWriteSS()
+    ut_snapshot()
+        .assertContent(
+            """
+            ╔═ selfie ═╗
+            apple
+            ╔═ [end of file] ═╗
+
+        """
+                .trimIndent())
+  }
+
+  @Test @Order(3)
+  fun assertApplePasses() {
+    gradleReadSS()
+  }
+
+  @Test @Order(4)
+  fun assertOrangeFails() {
+    ut_mirror().lineWith("apple").commentOut()
+    ut_mirror().lineWith("orange").uncomment()
+    gradleReadSSFail()
+    ut_snapshot()
+        .assertContent(
+            """
+            ╔═ selfie ═╗
+            apple
+            ╔═ [end of file] ═╗
+
+        """
+                .trimIndent())
+  }
+
+  @Test @Order(5)
+  fun writeOrange() {
+    gradleWriteSS()
+    ut_snapshot()
+        .assertContent(
+            """
+            ╔═ selfie ═╗
+            orange
+            ╔═ [end of file] ═╗
+
+        """
+                .trimIndent())
+  }
+}

settings.gradle

@@ -42,4 +42,5 @@ blowdryerSetup {
 include 'selfie-lib'
 include 'selfie-runner-junit5'
 include 'undertest-junit5'
+include 'undertest-junit-vintage'
 rootProject.name = 'selfie'

undertest-junit-vintage/build.gradle

@@ -0,0 +1,48 @@
+plugins {
+  id 'org.jetbrains.kotlin.jvm'
+}
+repositories {
+  mavenCentral()
+}
+apply plugin: 'com.diffplug.spotless'
+spotless {
+  kotlin {
+    target 'src/**/*.kt'
+    toggleOffOn()
+    licenseHeader ''
+    ktfmt()
+    replaceRegex("test one-liner", "@Test\n(\\s*)fun ", "@Test fun ")
+    replaceRegex("test harness comments", "\n(\\s)*//", "\n//")
+  }
+}
+
+dependencies {
+  testImplementation project(':selfie-runner-junit5')
+  testCompileOnly "junit:junit:4.13.2"
+  testImplementation "org.junit.jupiter:junit-jupiter-api:${ver_JUNIT_USE}"
+  testImplementation "org.junit.vintage:junit-vintage-engine:${ver_JUNIT_USE}"
+}
+// this project is just a test environment for a different project
+test {
+  enabled = false
+}
+tasks.register('underTest', Test) {
+  useJUnitPlatform()
+  testClassesDirs = testing.suites.test.sources.output.classesDirs
+  classpath = testing.suites.test.sources.runtimeClasspath
+  testLogging.showStandardStreams = true
+  // the snapshots are both output and input, for this harness best if the test just always runs
+  outputs.upToDateWhen { false }
+  // defaults to 'write'
+  systemProperty 'selfie', findProperty('selfie')
+}
+tasks.register('underTestRead', Test) {
+  useJUnitPlatform()
+  testClassesDirs = testing.suites.test.sources.output.classesDirs
+  classpath = testing.suites.test.sources.runtimeClasspath
+  testLogging.showStandardStreams = true
+  // the snapshots are both output and input, for this harness best if the test just always runs
+  outputs.upToDateWhen { false }
+  // read-only
+  systemProperty 'selfie', 'read'
+}

undertest-junit-vintage/src/test/kotlin/undertest/junit5/UT_ReadWriteVintageTest.kt

@@ -0,0 +1,11 @@
+package undertest.junit5
+
+import com.diffplug.selfie.Selfie.expectSelfie
+import org.junit.Test
+
+class UT_ReadWriteVintageTest {
+  @Test fun selfie() {
+//    expectSelfie("apple").toMatchDisk()
+    expectSelfie("orange").toMatchDisk()
+  }
+}

undertest-junit-vintage/src/test/kotlin/undertest/junit5/__snapshots__/UT_ReadWriteVintageTest.ss

@@ -0,0 +1,3 @@
+╔═ selfie ═╗
+orange
+╔═ [end of file] ═╗

undertest-junit5/build.gradle

@@ -29,6 +29,7 @@ tasks.register('underTest', Test) {
   useJUnitPlatform()
   testClassesDirs = testing.suites.test.sources.output.classesDirs
   classpath = testing.suites.test.sources.runtimeClasspath
+  testLogging.showStandardStreams = true
   // the snapshots are both output and input, for this harness best if the test just always runs
   outputs.upToDateWhen { false }
   // defaults to 'write'
@@ -38,6 +39,7 @@ tasks.register('underTestRead', Test) {
   useJUnitPlatform()
   testClassesDirs = testing.suites.test.sources.output.classesDirs
   classpath = testing.suites.test.sources.runtimeClasspath
+  testLogging.showStandardStreams = true
   // the snapshots are both output and input, for this harness best if the test just always runs
   outputs.upToDateWhen { false }
   // read-only