Pre: Allow to set NDK version in tests; test multiple NDK versions.

Author: ncalexan

plugin/src/test/groovy/com/nishtahir/NdkVersionTest.groovy

@@ -0,0 +1,57 @@
+package com.nishtahir
+
+import org.gradle.testkit.runner.BuildResult
+import org.gradle.testkit.runner.TaskOutcome
+import spock.lang.Unroll
+
+import com.nishtahir.Versions
+
+class NdkVersionTest extends AbstractTest {
+    @Unroll
+    def "cargoBuild works with Android NDK version #ndkVersion"() {
+        given:
+        def androidVersion = TestVersions.latestAndroidVersionForCurrentJDK()
+        def target = "x86_64"
+        def location = "android/x86_64/librust.so"
+
+        SimpleAndroidApp.builder(temporaryFolder.root, cacheDir)
+                .withAndroidVersion(androidVersion)
+                .withNdkVersion(ndkVersion)
+                .withKotlinDisabled()
+        // TODO: .withCargo(...)
+                .build()
+                .writeProject()
+
+        SimpleCargoProject.builder(temporaryFolder.root)
+                .withTargets([target])
+                .build()
+                .writeProject()
+
+        when:
+        BuildResult buildResult = withGradleVersion(TestVersions.latestSupportedGradleVersionFor(androidVersion).version)
+                .withProjectDir(temporaryFolder.root)
+                .withArguments('cargoBuild', '--info', '--stacktrace')
+        // .withDebug(true)
+                .build()
+
+        // To ease debugging.
+        temporaryFolder.root.eachFileRecurse {
+            println(it)
+        }
+
+        then:
+        buildResult.task(':app:cargoBuild').outcome == TaskOutcome.SUCCESS
+        buildResult.task(':library:cargoBuild').outcome == TaskOutcome.SUCCESS
+        new File(temporaryFolder.root, "app/build/rustJniLibs/${location}").exists()
+        new File(temporaryFolder.root, "library/build/rustJniLibs/${location}").exists()
+
+        where:
+        ndkVersion << [
+            // NDK versions supported by Github Actions, per
+            // https://github.com/actions/virtual-environments/blob/main/images/linux/Ubuntu2004-Readme.md.
+            "21.4.7075529",
+            "22.1.7171670",
+            "23.1.7779620",
+        ]
+    }
+}

plugin/src/test/groovy/com/nishtahir/SimpleAndroidApp.groovy

@@ -9,14 +9,16 @@ class SimpleAndroidApp {
     final File projectDir
     private final File cacheDir
     final VersionNumber androidVersion
+    final VersionNumber ndkVersion
     final VersionNumber kotlinVersion
     private final boolean kotlinEnabled
     private final boolean kaptWorkersEnabled
 
-    private SimpleAndroidApp(File projectDir, File cacheDir, VersionNumber androidVersion, VersionNumber kotlinVersion, boolean kotlinEnabled, boolean kaptWorkersEnabled) {
+    private SimpleAndroidApp(File projectDir, File cacheDir, VersionNumber androidVersion, VersionNumber ndkVersion, VersionNumber kotlinVersion, boolean kotlinEnabled, boolean kaptWorkersEnabled) {
         this.projectDir = projectDir
         this.cacheDir = cacheDir
         this.androidVersion = androidVersion
+        this.ndkVersion = ndkVersion
         this.kotlinVersion = kotlinVersion
         this.kotlinEnabled = kotlinEnabled
         this.kaptWorkersEnabled = kaptWorkersEnabled
@@ -136,7 +138,7 @@ class SimpleAndroidApp {
             }
 
             android {
-                ${ndkVersion}
+                ${maybeNdkVersion}
                 compileSdkVersion 28
                 buildToolsVersion "29.0.3"
                 defaultConfig {
@@ -151,10 +153,10 @@ class SimpleAndroidApp {
         """.stripIndent()
     }
 
-    private String getNdkVersion() {
+    private String getMaybeNdkVersion() {
         def isAndroid34x = androidVersion >= android("3.4.0")
         if (isAndroid34x) {
-            return """ndkVersion '21.4.7075529'"""
+            return """ndkVersion '${ndkVersion}'"""
         } else {
             return ""
         }
@@ -271,6 +273,8 @@ class SimpleAndroidApp {
         boolean kaptWorkersEnabled = true
 
         VersionNumber androidVersion = Versions.latestAndroidVersion()
+        VersionNumber ndkVersion = Versions.latestAndroidVersion() >= android("3.4.0") ? VersionNumber.parse("21.4.7075529") : null
+
         VersionNumber kotlinVersion = VersionNumber.parse("1.3.72")
         File projectDir
         File cacheDir
@@ -297,13 +301,25 @@ class SimpleAndroidApp {
 
         Builder withAndroidVersion(VersionNumber androidVersion) {
             this.androidVersion = androidVersion
+            if (this.androidVersion < android("3.4.0")) {
+                this.ndkVersion = null
+            }
             return this
         }
 
         Builder withAndroidVersion(String androidVersion) {
             return withAndroidVersion(android(androidVersion))
         }
 
+        Builder withNdkVersion(VersionNumber ndkVersion) {
+            this.ndkVersion = ndkVersion
+            return this
+        }
+
+        Builder withNdkVersion(String ndkVersion) {
+            return withNdkVersion(VersionNumber.parse(ndkVersion))
+        }
+
         Builder withProjectDir(File projectDir) {
             this.projectDir = projectDir
             return this
@@ -315,7 +331,7 @@ class SimpleAndroidApp {
         }
 
         SimpleAndroidApp build() {
-            return new SimpleAndroidApp(projectDir, cacheDir, androidVersion, kotlinVersion, kotlinEnabled, kaptWorkersEnabled)
+            return new SimpleAndroidApp(projectDir, cacheDir, androidVersion, ndkVersion, kotlinVersion, kotlinEnabled, kaptWorkersEnabled)
         }
     }
 }