google: check additional AWS variable

AWS_DEFAULT_REGION should have been checked as a backup to AWS_REGION but wasn't.  Also removed a redundant print statement in a test case.

Change-Id: Ia6e13eb20f509110a81e3071228283c43a1e9283
GitHub-Last-Rev: 1a10bcc0791f862983c3e3ae36f0cb73e29db267
GitHub-Pull-Request: golang/oauth2#486
Reviewed-on: https://go-review.googlesource.com/c/oauth2/+/302789
Reviewed-by: Cody Oss <codyoss@google.com>
Trust: Cody Oss <codyoss@google.com>
Trust: Tyler Bui-Palsulich <tbp@google.com>

google/internal/externalaccount/aws.go

@@ -342,6 +342,8 @@ func (cs awsCredentialSource) subjectToken() (string, error) {
 func (cs *awsCredentialSource) getRegion() (string, error) {
 	if envAwsRegion := getenv("AWS_REGION"); envAwsRegion != "" {
 		return envAwsRegion, nil
+	} if envAwsRegion := getenv("AWS_DEFAULT_REGION"); envAwsRegion != "" {
+		return envAwsRegion, nil
 	}
 
 	if cs.RegionURL == "" {

google/internal/externalaccount/aws_test.go

@@ -638,6 +638,81 @@ func TestAwsCredential_BasicRequestWithEnv(t *testing.T) {
 	}
 }
 
+func TestAwsCredential_BasicRequestWithDefaultEnv(t *testing.T) {
+	server := createDefaultAwsTestServer()
+	ts := httptest.NewServer(server)
+
+	tfc := testFileConfig
+	tfc.CredentialSource = server.getCredentialSource(ts.URL)
+
+	oldGetenv := getenv
+	defer func() { getenv = oldGetenv }()
+	getenv = setEnvironment(map[string]string{
+		"AWS_ACCESS_KEY_ID":     "AKIDEXAMPLE",
+		"AWS_SECRET_ACCESS_KEY": "wJalrXUtnFEMI/K7MDENG+bPxRfiCYEXAMPLEKEY",
+		"AWS_DEFAULT_REGION":            "us-west-1",
+	})
+
+	base, err := tfc.parse(context.Background())
+	if err != nil {
+		t.Fatalf("parse() failed %v", err)
+	}
+
+	out, err := base.subjectToken()
+	if err != nil {
+		t.Fatalf("retrieveSubjectToken() failed: %v", err)
+	}
+	expected := getExpectedSubjectToken(
+		"https://sts.us-west-1.amazonaws.com?Action=GetCallerIdentity&Version=2011-06-15",
+		"us-west-1",
+		"AKIDEXAMPLE",
+		"wJalrXUtnFEMI/K7MDENG+bPxRfiCYEXAMPLEKEY",
+		"",
+	)
+
+	if got, want := out, expected; !reflect.DeepEqual(got, want) {
+		t.Errorf("subjectToken = %q, want %q", got, want)
+	}
+}
+
+func TestAwsCredential_BasicRequestWithTwoRegions(t *testing.T) {
+	server := createDefaultAwsTestServer()
+	ts := httptest.NewServer(server)
+
+	tfc := testFileConfig
+	tfc.CredentialSource = server.getCredentialSource(ts.URL)
+
+	oldGetenv := getenv
+	defer func() { getenv = oldGetenv }()
+	getenv = setEnvironment(map[string]string{
+		"AWS_ACCESS_KEY_ID":     "AKIDEXAMPLE",
+		"AWS_SECRET_ACCESS_KEY": "wJalrXUtnFEMI/K7MDENG+bPxRfiCYEXAMPLEKEY",
+		"AWS_REGION":            "us-west-1",
+		"AWS_DEFAULT_REGION":            "us-east-1",
+	})
+
+	base, err := tfc.parse(context.Background())
+	if err != nil {
+		t.Fatalf("parse() failed %v", err)
+	}
+
+	out, err := base.subjectToken()
+	if err != nil {
+		t.Fatalf("retrieveSubjectToken() failed: %v", err)
+	}
+	expected := getExpectedSubjectToken(
+		"https://sts.us-west-1.amazonaws.com?Action=GetCallerIdentity&Version=2011-06-15",
+		"us-west-1",
+		"AKIDEXAMPLE",
+		"wJalrXUtnFEMI/K7MDENG+bPxRfiCYEXAMPLEKEY",
+		"",
+	)
+
+	if got, want := out, expected; !reflect.DeepEqual(got, want) {
+		t.Errorf("subjectToken = %q, want %q", got, want)
+	}
+}
+
 func TestAwsCredential_RequestWithBadVersion(t *testing.T) {
 	server := createDefaultAwsTestServer()
 	ts := httptest.NewServer(server)

google/internal/externalaccount/urlcredsource_test.go

@@ -7,7 +7,6 @@ package externalaccount
 import (
 	"context"
 	"encoding/json"
-	"fmt"
 	"net/http"
 	"net/http/httptest"
 	"testing"
@@ -20,7 +19,6 @@ func TestRetrieveURLSubjectToken_Text(t *testing.T) {
 		if r.Method != "GET" {
 			t.Errorf("Unexpected request method, %v is found", r.Method)
 		}
-		fmt.Println(r.Header)
 		if r.Header.Get("Metadata") != "True" {
 			t.Errorf("Metadata header not properly included.")
 		}