Migrate all tests to kotlin, remove groovy plugin from buildSrc.

buildSrc/build.gradle

@@ -13,8 +13,8 @@
 // limitations under the License.
 
 plugins {
-    id 'java-gradle-plugin'
-    id 'groovy'
+    id "org.gradle.kotlin.kotlin-dsl" version "1.2.6"
+    id "org.jlleitschuh.gradle.ktlint" version "9.2.1"
 }
 
 repositories {
@@ -42,21 +42,16 @@ dependencies {
     implementation 'digital.wup:android-maven-publish:3.6.2'
     implementation 'org.jetbrains.kotlin:kotlin-gradle-plugin:1.3.20'
     implementation 'org.json:json:20180813'
-
     implementation 'io.opencensus:opencensus-api:0.18.0'
     implementation 'io.opencensus:opencensus-exporter-stats-stackdriver:0.18.0'
     runtime 'io.opencensus:opencensus-impl:0.18.0'
     implementation group: 'com.google.code.gson', name: 'gson', version: '2.8.6'
-
     implementation 'org.jetbrains.dokka:dokka-android-gradle-plugin:0.9.17-g008'
-
     implementation 'com.android.tools.build:gradle:3.4.1'
-    testImplementation 'junit:junit:4.12'
-    testImplementation group: 'com.google.code.gson', name: 'gson', version: '2.8.6'
-    testImplementation('org.spockframework:spock-core:1.1-groovy-2.4') {
-        exclude group: 'org.codehaus.groovy'
-    }
 
+    testImplementation 'junit:junit:4.13-rc-1'
+    testImplementation group: 'com.google.code.gson', name: 'gson', version: '2.8.6'
+    testImplementation "com.google.truth:truth:1.0.1"
     testImplementation 'commons-io:commons-io:2.6'
 
 }

buildSrc/src/test/kotlin/com/google/firebase/gradle/plugins/LicenseResolverPluginTests.kt

@@ -0,0 +1,147 @@
+// Copyright 2020 Google LLC
+//
+// 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
+//
+//      http://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.google.firebase.gradle.plugins
+
+import com.google.common.truth.Truth.assertThat
+import com.google.gson.Gson
+import com.google.gson.reflect.TypeToken
+import java.io.File
+import org.gradle.testkit.runner.BuildResult
+import org.gradle.testkit.runner.GradleRunner
+import org.gradle.testkit.runner.TaskOutcome
+import org.gradle.testkit.runner.UnexpectedBuildFailure
+import org.junit.Assert
+import org.junit.Before
+import org.junit.Rule
+import org.junit.Test
+import org.junit.rules.TemporaryFolder
+import org.junit.runner.RunWith
+import org.junit.runners.JUnit4
+
+@RunWith(JUnit4::class)
+class LicenseResolverPluginTests {
+
+    @Rule
+    @JvmField
+    val testProjectDir = TemporaryFolder()
+    private lateinit var buildFile: File
+
+    val idempotentBuild: (taskName: String) -> BuildResult
+        get() = this::build.memoize()
+
+    @Before
+    fun setup() {
+        buildFile = testProjectDir.newFile("build.gradle")
+        testProjectDir.newFolder("src", "main", "java", "com", "example")
+        testProjectDir.newFile("src/main/java/com/example/Foo.java").writeText("package com.example; class Foo {}")
+        testProjectDir.newFile("src/main/AndroidManifest.xml").writeText(MANIFEST)
+
+        buildFile.writeText(BUILD_CONFIG)
+    }
+
+    @Test
+    fun `Generating licenses`() {
+        val result = idempotentBuild("generateLicenses")
+        assertThat(result.task(":generateLicenses")?.outcome).isEqualTo(TaskOutcome.SUCCESS)
+
+        val json = getLicenseJson()
+        val txt = getLicenseText()
+
+        assertThat(txt).isNotEmpty()
+
+        assertThat(json).containsKey("customLib1")
+
+        assertThat(txt).contains("customLib1")
+        assertThat(txt).contains("Test license")
+        val (start, length) = json["customLib1"]!!
+        assertThat(txt.substring(start, start + length).trim()).isEqualTo("Test license")
+    }
+
+    @Test
+    fun `License tasks throw useful exception if file URI not found`() {
+        buildFile.writeText("""
+            plugins {
+                id 'com.android.library'
+                id 'LicenseResolverPlugin'
+            }
+            android.compileSdkVersion = 26
+
+            thirdPartyLicenses {
+                add 'customLib', "file:///${File("non_existent_path.txt").absolutePath}"
+            }
+        """)
+
+        val thrown = Assert.assertThrows(UnexpectedBuildFailure::class.java) {
+            build("generateLicenses")
+        }
+
+        assertThat(thrown.message).contains("License file not found")
+    }
+
+    data class FileOffset(val start: Int, val length: Int)
+
+    private fun getLicenseJson(): Map<String, FileOffset> =
+            Gson().fromJson(
+                    File("${testProjectDir.root}/build/generated/third_party_licenses/",
+                            "third_party_licenses.json").readText(),
+                    object : TypeToken<Map<String, FileOffset>>() {}.type)
+
+    private fun getLicenseText(): String =
+            File("${testProjectDir.root}/build/generated/third_party_licenses/",
+                    "third_party_licenses.txt").readText()
+
+    private fun build(taskName: String): BuildResult = GradleRunner.create()
+            .withProjectDir(testProjectDir.root)
+            .withArguments(taskName, "--stacktrace")
+            .withPluginClasspath()
+            .build()
+
+    companion object {
+        const val MANIFEST = """<?xml version="1.0" encoding="utf-8"?>
+        <manifest xmlns:android="http://schemas.android.com/apk/res/android"
+                  package="com.example">
+            <uses-sdk android:minSdkVersion="14"/>
+        </manifest>
+    """
+        val BUILD_CONFIG = """
+        buildscript {
+            repositories {
+                google()
+                jcenter()
+            }
+        }
+
+        plugins {
+            id 'com.android.library'
+            id 'LicenseResolverPlugin'
+        }
+
+        android.compileSdkVersion = 26
+
+        repositories {
+            jcenter()
+            google()
+        }
+        dependencies {
+            implementation 'com.squareup.picasso:picasso:2.71828'
+            implementation 'com.squareup.okhttp:okhttp:2.7.5'
+        }
+
+        thirdPartyLicenses {
+            add 'customLib1', "file:///${File("src/test/fixtures/license.txt").absolutePath}"
+        }
+        """
+    }
+}

buildSrc/src/test/kotlin/com/google/firebase/gradle/plugins/Memoization.kt

@@ -0,0 +1,24 @@
+// Copyright 2020 Google LLC
+//
+// 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
+//
+//      http://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.google.firebase.gradle.plugins
+
+class Memoize1<in T, out R>(val f: (T) -> R) : (T) -> R {
+    private val values = mutableMapOf<T, R>()
+    override fun invoke(x: T): R {
+        return values.getOrPut(x, { f(x) })
+    }
+}
+
+fun <T, R> ((T) -> R).memoize(): (T) -> R = Memoize1(this)