Implement FSOkio, templated from FSJava (#188)

jvm/selfie-lib/src/commonMain/kotlin/com/diffplug/selfie/guts/SnapshotStorage.kt

@@ -71,7 +71,7 @@ interface FS {
   fun fileRead(typedPath: TypedPath): String
   fun fileWrite(typedPath: TypedPath, content: String)
   /** Creates an assertion failed exception to throw. */
-  fun assertFailed(message: String, expected: Any? = null, actual: Any? = null): Error
+  fun assertFailed(message: String, expected: Any? = null, actual: Any? = null): Throwable
 }
 
 /** NOT FOR ENDUSERS. Implemented by Selfie to integrate with various test frameworks. */

jvm/selfie-runner-kotest/build.gradle

@@ -28,6 +28,7 @@ kotlin {
       dependencies {
         api project(":selfie-lib")
         api "io.kotest:kotest-framework-engine:$ver_KOTEST"
+        api "io.kotest:kotest-assertions-shared:$ver_KOTEST"
         implementation "com.squareup.okio:okio:$ver_OKIO"
       }
     }

jvm/selfie-runner-kotest/src/commonMain/kotlin/com/diffplug/selfie/kotest/FSOkio.kt

@@ -0,0 +1,62 @@
+/*
+ * Copyright (C) 2024 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.kotest
+
+import com.diffplug.selfie.guts.FS
+import com.diffplug.selfie.guts.TypedPath
+import io.kotest.assertions.Actual
+import io.kotest.assertions.Exceptions
+import io.kotest.assertions.Expected
+import io.kotest.assertions.print.Printed
+import okio.FileSystem
+import okio.Path.Companion.toPath
+
+expect internal val FS_SYSTEM: FileSystem
+fun TypedPath.toPath(): okio.Path = absolutePath.toPath()
+
+object FSOkio : FS {
+  /** Walks the files (not directories) which are children and grandchildren of the given path. */
+  override fun <T> fileWalk(typedPath: TypedPath, walk: (Sequence<TypedPath>) -> T): T =
+      walk(
+          FS_SYSTEM.listRecursively(typedPath.toPath()).mapNotNull {
+            if (FS_SYSTEM.metadata(it).isRegularFile) TypedPath.ofFile(it.toString()) else null
+          })
+  override fun fileRead(typedPath: TypedPath): String =
+      FS_SYSTEM.read(typedPath.toPath()) { readUtf8() }
+  override fun fileWrite(typedPath: TypedPath, content: String): Unit =
+      FS_SYSTEM.write(typedPath.toPath()) { writeUtf8(content) }
+  /** Creates an assertion failed exception to throw. */
+  override fun assertFailed(message: String, expected: Any?, actual: Any?): Throwable =
+      if (expected == null && actual == null) Exceptions.createAssertionError(message, null)
+      else {
+        val expectedStr = nullableToString(expected, "")
+        val actualStr = nullableToString(actual, "")
+        if (expectedStr.isEmpty() && actualStr.isEmpty() && (expected == null || actual == null)) {
+          // make sure that nulls are not ambiguous
+          val onNull = "(null)"
+          comparisonAssertion(
+              message, nullableToString(expected, onNull), nullableToString(actual, onNull))
+        } else {
+          comparisonAssertion(message, expectedStr, actualStr)
+        }
+      }
+  private fun nullableToString(any: Any?, onNull: String): String =
+      any?.let { it.toString() } ?: onNull
+  private fun comparisonAssertion(message: String, expected: String, actual: String): Throwable {
+    return Exceptions.createAssertionError(
+        message, null, Expected(Printed((expected))), Actual(Printed((actual))))
+  }
+}

jvm/selfie-runner-kotest/src/commonTest/kotlin/com/diffplug/selfie/kotest/HarnessKotest.kt

@@ -19,11 +19,9 @@ import com.diffplug.selfie.guts.TypedPath
 import io.kotest.core.spec.style.StringSpec
 import io.kotest.core.test.TestCaseOrder
 import io.kotest.matchers.shouldBe
-import okio.FileSystem
 import okio.Path
 import okio.Path.Companion.toPath
 
-expect val FS_SYSTEM: FileSystem
 expect val IS_WINDOWS: Boolean
 
 expect fun exec(cwd: TypedPath, vararg args: String): String

jvm/selfie-runner-kotest/src/jsMain/kotlin/com/diffplug/selfie/kotest/FSOkio.js.kt

@@ -0,0 +1,21 @@
+/*
+ * Copyright (C) 2024 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.kotest
+
+import okio.FileSystem
+
+internal actual val FS_SYSTEM: FileSystem
+  get() = okio.NodeJsFileSystem

jvm/selfie-runner-kotest/src/jsTest/kotlin/com/diffplug/selfie/kotest/HarnessKotest.js.kt

@@ -16,9 +16,6 @@
 package com.diffplug.selfie.kotest
 
 import com.diffplug.selfie.guts.TypedPath
-import okio.FileSystem
-actual val FS_SYSTEM: FileSystem
-  get() = okio.NodeJsFileSystem
 actual val IS_WINDOWS: Boolean
   get() = TODO("Not yet implemented")
 actual fun exec(cwd: TypedPath, vararg args: String): String {

jvm/selfie-runner-kotest/src/jvmMain/kotlin/com/diffplug/selfie/kotest/FSOkio.jvm.kt

@@ -0,0 +1,21 @@
+/*
+ * Copyright (C) 2024 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.kotest
+
+import okio.FileSystem
+
+internal actual val FS_SYSTEM: FileSystem
+  get() = FileSystem.SYSTEM

jvm/selfie-runner-kotest/src/jvmTest/kotlin/com/diffplug/selfie/kotest/HarnessKotest.jvm.kt

@@ -19,9 +19,6 @@ import com.diffplug.selfie.guts.TypedPath
 import java.io.BufferedReader
 import java.io.File
 import java.io.InputStreamReader
-import okio.FileSystem
-actual val FS_SYSTEM: FileSystem
-  get() = FileSystem.SYSTEM
 actual val IS_WINDOWS: Boolean
   get() = System.getProperty("os.name").lowercase().contains("windows")
 actual fun exec(cwd: TypedPath, vararg args: String): String {