chore: Add unit tests for setting the source

Author: lqiu96

oauth2_http/java/com/google/auth/oauth2/ComputeEngineCredentials.java

@@ -692,7 +692,6 @@ public String getAccount() {
     if (serviceAccountEmail == null) {
       try {
         serviceAccountEmail = getDefaultServiceAccount();
-        this.principal = serviceAccountEmail;
       } catch (IOException ex) {
         throw new RuntimeException("Failed to get service account", ex);
       }
@@ -763,7 +762,9 @@ private String getDefaultServiceAccount() throws IOException {
         responseData, LOGGER_PROVIDER, "Received default service account payload");
     Map<String, Object> defaultAccount =
         OAuth2Utils.validateMap(responseData, "default", PARSE_ERROR_ACCOUNT);
-    return OAuth2Utils.validateString(defaultAccount, "email", PARSE_ERROR_ACCOUNT);
+    String email = OAuth2Utils.validateString(defaultAccount, "email", PARSE_ERROR_ACCOUNT);
+    principal = email;
+    return email;
   }
 
   public static class Builder extends GoogleCredentials.Builder {

oauth2_http/java/com/google/auth/oauth2/DefaultCredentialsProvider.java

@@ -223,7 +223,7 @@ private final GoogleCredentials getDefaultCredentialsUnsynchronized(
         credentials =
             credentials.withSource(
                 String.format(
-                    "Metadata Server URL set to %s", System.getenv(GCE_METADATA_HOST_ENV_VAR)));
+                    "Metadata Server URL set to %s", getEnv(GCE_METADATA_HOST_ENV_VAR)));
       }
     }
 

oauth2_http/javatests/com/google/auth/oauth2/DefaultCredentialsProviderTest.java

@@ -742,6 +742,104 @@ public AccessToken refreshAccessToken() throws IOException {
     }
   }
 
+  @Test
+  public void getDefaultCredentials_envVarSet_serviceAccountCredentials_correctCredentialInfo() throws IOException {
+    MockTokenServerTransportFactory transportFactory =
+            new MockTokenServerTransportFactory();
+    transportFactory.transport.addServiceAccount(SA_CLIENT_EMAIL, ACCESS_TOKEN);
+    InputStream serviceAccountStream =
+            ServiceAccountCredentialsTest.writeServiceAccountStream(
+                    SA_CLIENT_ID, SA_CLIENT_EMAIL, SA_PRIVATE_KEY_PKCS8, SA_PRIVATE_KEY_ID);
+    TestDefaultCredentialsProvider testProvider = new TestDefaultCredentialsProvider();
+    String serviceAccountPath = tempFilePath("service_account.json");
+    testProvider.addFile(serviceAccountPath, serviceAccountStream);
+    testProvider.setEnv(DefaultCredentialsProvider.CREDENTIAL_ENV_VAR, serviceAccountPath);
+
+    GoogleCredentials credentials = testProvider.getDefaultCredentials(transportFactory);
+
+    assertNotNull(credentials);
+    assertTrue(credentials instanceof ServiceAccountCredentials);
+    Map<String, String> credentialInfo = credentials.getCredentialInfo();
+    assertEquals(
+            String.format(
+                    "Env Var %s set to %s",
+                    DefaultCredentialsProvider.CREDENTIAL_ENV_VAR, serviceAccountPath),
+            credentialInfo.get("Credential Source"));
+    assertEquals("Service Account Credentials", credentialInfo.get("Credential Type"));
+    assertEquals(SA_CLIENT_EMAIL, credentialInfo.get("Principal"));
+  }
+
+  @Test
+  public void getDefaultCredentials_envVarSet_userCredential_correctCredentialInfo() throws IOException {
+    InputStream userStream =
+            UserCredentialsTest.writeUserStream(
+                    USER_CLIENT_ID, USER_CLIENT_SECRET, REFRESH_TOKEN, QUOTA_PROJECT);
+    TestDefaultCredentialsProvider testProvider = new TestDefaultCredentialsProvider();
+    String userPath = tempFilePath("user.json");
+    testProvider.addFile(userPath, userStream);
+    testProvider.setEnv(DefaultCredentialsProvider.CREDENTIAL_ENV_VAR, userPath);
+    HttpTransportFactory transportFactory =
+            new MockTokenServerTransportFactory();
+
+    GoogleCredentials credentials = testProvider.getDefaultCredentials(transportFactory);
+
+    assertNotNull(credentials);
+    assertTrue(credentials instanceof UserCredentials);
+    Map<String, String> credentialInfo = credentials.getCredentialInfo();
+    assertEquals(
+            String.format(
+                    "Env Var %s set to %s",
+                    DefaultCredentialsProvider.CREDENTIAL_ENV_VAR, userPath),
+            credentialInfo.get("Credential Source"));
+    assertEquals("User Credentials", credentialInfo.get("Credential Type"));
+    assertNull(credentialInfo.get("Principal"));
+  }
+
+  @Test
+  public void getDefaultCredentials_wellKnownFile_userCredential_correctCredentialInfo() throws IOException {
+    File cloudConfigDir = getTempDirectory();
+    InputStream userStream =
+            UserCredentialsTest.writeUserStream(
+                    USER_CLIENT_ID, USER_CLIENT_SECRET, REFRESH_TOKEN, QUOTA_PROJECT);
+    File wellKnownFile =
+            new File(cloudConfigDir, DefaultCredentialsProvider.WELL_KNOWN_CREDENTIALS_FILE);
+    TestDefaultCredentialsProvider testProvider = new TestDefaultCredentialsProvider();
+    testProvider.setEnv("CLOUDSDK_CONFIG", cloudConfigDir.getAbsolutePath());
+    testProvider.addFile(wellKnownFile.getAbsolutePath(), userStream);
+    HttpTransportFactory transportFactory =
+            new MockTokenServerTransportFactory();
+
+    GoogleCredentials credentials = testProvider.getDefaultCredentials(transportFactory);
+
+    assertNotNull(credentials);
+    assertTrue(credentials instanceof UserCredentials);
+    Map<String, String> credentialInfo = credentials.getCredentialInfo();
+    assertEquals(
+            String.format("Well Known File at %s", wellKnownFile.getCanonicalPath()),
+            credentialInfo.get("Credential Source"));
+    assertEquals("User Credentials", credentialInfo.get("Credential Type"));
+    assertNull(credentialInfo.get("Principal"));
+  }
+
+  @Test
+  public void getDefaultCredentials_computeEngineCredentialscorrectCredentialInfo() throws IOException {
+    MockMetadataServerTransportFactory transportFactory = new MockMetadataServerTransportFactory();
+    TestDefaultCredentialsProvider testProvider = new TestDefaultCredentialsProvider();
+    String gceMetadataHost = "192.0.2.0";
+    testProvider.setEnv(DefaultCredentialsProvider.GCE_METADATA_HOST_ENV_VAR, gceMetadataHost);
+
+    GoogleCredentials credentials = testProvider.getDefaultCredentials(transportFactory);
+
+    assertNotNull(credentials);
+    assertTrue(credentials instanceof ComputeEngineCredentials);
+    Map<String, String> credentialInfo = credentials.getCredentialInfo();
+    assertEquals(
+            String.format("Metadata Server URL set to %s", gceMetadataHost),
+            credentials.getCredentialInfo().get("Credential Source"));
+    assertEquals("Compute Engine Credentials", credentialInfo.get("Credential Type"));
+    assertNull(credentialInfo.get("Principal"));
+  }
+
   /*
    * App Engine is detected by calling SystemProperty.environment.value() via Reflection.
    * The following mock types simulate the shape and behavior of that call sequence.
@@ -898,4 +996,14 @@ public HttpTransport create() {
       return transport;
     }
   }
-}
+
+  static class MockTokenServerTransportFactory implements HttpTransportFactory {
+
+    MockTokenServerTransport transport = new MockTokenServerTransport();
+
+    @Override
+    public HttpTransport create() {
+      return transport;
+    }
+  }
+}