diff --git a/google/internal/externalaccount/basecredentials_test.go b/google/internal/externalaccount/basecredentials_test.go
index 107ed4a..823fce9 100644
--- a/google/internal/externalaccount/basecredentials_test.go
+++ b/google/internal/externalaccount/basecredentials_test.go
@@ -14,7 +14,8 @@ import (
 )
 
 var testBaseCredSource = CredentialSource{
-	File: "internalTestingFile",
+	File:   "./testdata/3pi_cred.txt",
+	Format: format{Type: fileTypeText},
 }
 
 var testConfig = Config{
@@ -29,7 +30,7 @@ var testConfig = Config{
 }
 
 var (
-	baseCredsRequestBody        = "audience=32555940559.apps.googleusercontent.com&grant_type=urn%3Aietf%3Aparams%3Aoauth%3Agrant-type%3Atoken-exchange&options=null&requested_token_type=urn%3Aietf%3Aparams%3Aoauth%3Atoken-type%3Aaccess_token&scope=https%3A%2F%2Fwww.googleapis.com%2Fauth%2Fdevstorage.full_control&subject_token=Sample.Subject.Token&subject_token_type=urn%3Aietf%3Aparams%3Aoauth%3Atoken-type%3Ajwt"
+	baseCredsRequestBody        = "audience=32555940559.apps.googleusercontent.com&grant_type=urn%3Aietf%3Aparams%3Aoauth%3Agrant-type%3Atoken-exchange&options=null&requested_token_type=urn%3Aietf%3Aparams%3Aoauth%3Atoken-type%3Aaccess_token&scope=https%3A%2F%2Fwww.googleapis.com%2Fauth%2Fdevstorage.full_control&subject_token=street123&subject_token_type=urn%3Aietf%3Aparams%3Aoauth%3Atoken-type%3Ajwt"
 	baseCredsResponseBody       = `{"access_token":"Sample.Access.Token","issued_token_type":"urn:ietf:params:oauth:token-type:access_token","token_type":"Bearer","expires_in":3600,"scope":"https://www.googleapis.com/auth/cloud-platform"}`
 	correctAT                   = "Sample.Access.Token"
 	expiry                int64 = 234852
diff --git a/google/internal/externalaccount/filecredsource_test.go b/google/internal/externalaccount/filecredsource_test.go
index f6829cb..b6e36ba 100644
--- a/google/internal/externalaccount/filecredsource_test.go
+++ b/google/internal/externalaccount/filecredsource_test.go
@@ -53,7 +53,7 @@ func TestRetrieveFileSubjectToken(t *testing.T) {
 		tfc := testFileConfig
 		tfc.CredentialSource = test.cs
 
-		out, err := tfc.parse().retrieveSubjectToken(&tfc)
+		out, err := tfc.parse().subjectToken()
 		if err != nil {
 			t.Errorf("Method retrieveSubjectToken for type fileCredentialSource in test %v failed; %e", test.name, err)
 		}