Set test type to release only in CI.

This fixes Android Studio issue, where it is impossible to run
integration tests in debug mode.

Additionally move build type configuration to FirebaseLibraryPlugin to
avoid projects.all configuration in gradle.

Author: vkryachko

buildSrc/src/main/groovy/com/google/firebase/gradle/plugins/FirebaseLibraryPlugin.java

@@ -20,7 +20,6 @@
 import com.google.firebase.gradle.plugins.ci.device.FirebaseTestServer;
 import org.gradle.api.Plugin;
 import org.gradle.api.Project;
-import org.gradle.api.tasks.bundling.Jar;
 import org.jetbrains.kotlin.gradle.tasks.KotlinCompile;
 
 public class FirebaseLibraryPlugin implements Plugin<Project> {
@@ -32,6 +31,25 @@ public void apply(Project project) {
         project.getExtensions().create("firebaseLibrary", FirebaseLibraryExtension.class, project);
 
     LibraryExtension android = project.getExtensions().getByType(LibraryExtension.class);
+    android.buildTypes(
+        types ->
+            types
+                .getByName("release")
+                .setSigningConfig(types.getByName("debug").getSigningConfig()));
+
+    // skip debug tests in CI
+    // TODO(vkryachko): provide ability for teams to control this if needed
+    if (System.getenv().containsKey("FIREBASE_CI")) {
+      android.setTestBuildType("release");
+      project
+          .getTasks()
+          .all(
+              task -> {
+                if ("testDebugUnitTest".equals(task.getName())) {
+                  task.setEnabled(false);
+                }
+              });
+    }
 
     android.testServer(new FirebaseTestServer(project, firebaseLibrary.testLab));
 

root-project.gradle

@@ -140,38 +140,6 @@ configure(subprojects) {
     }
 }
 
-/**
- * Disable "debug" build type for all subprojects.
- *
- * They are identical to "release" and are not used in either release or smoke tests. Disabling them
- * to reduce the number of tests we run on pre/post-submit.
- */
-configure(subprojects) {
-    afterEvaluate { Project sub ->
-        if (!sub.plugins.hasPlugin('com.android.library') && !sub.plugins.hasPlugin('com.android.application')) {
-            return
-        }
-
-        // skip debug unit tests in CI
-        // TODO(vkryachko): provide ability for teams to control this if needed
-        if (System.getenv().containsKey("FIREBASE_CI")) {
-            sub.tasks.all {Task task ->
-                if (task.name == 'testDebugUnitTest') {
-                    task.enabled = false
-                }
-            }
-        }
-        sub.android {
-            testBuildType "release"
-
-            buildTypes {
-                // In the case of and android library signing config only affects instrumentation test APK.
-                // We need it signed with default debug credentials in order for FTL to accept the APK.
-                release.signingConfig = debug.signingConfig
-            }
-        }
-    }
-}
 
 /**
  * Configure "Preguarding" and Desugaring for the subprojects.