diff --git a/detectors/gcp/detector_test.go b/detectors/gcp/detector_test.go
index 705bcf0c..16a5f5e7 100644
--- a/detectors/gcp/detector_test.go
+++ b/detectors/gcp/detector_test.go
@@ -43,7 +43,11 @@ func TestCloudPlatformAppEngineStandard(t *testing.T) {
 }
 
 func TestCloudPlatformGKE(t *testing.T) {
-	d := NewTestDetector(&FakeMetadataProvider{}, &FakeOSProvider{
+	d := NewTestDetector(&FakeMetadataProvider{
+		InstanceAttributes: map[string]string{
+			clusterNameMetadataAttr: "cluster-name",
+		},
+	}, &FakeOSProvider{
 		Vars: map[string]string{
 			k8sServiceHostEnv: "foo",
 		},
@@ -53,12 +57,18 @@ func TestCloudPlatformGKE(t *testing.T) {
 }
 
 func TestCloudPlatformK8sNotGKE(t *testing.T) {
-	d := NewTestDetector(&FakeMetadataProvider{Err: fmt.Errorf("foo")}, &FakeOSProvider{
+	d := NewTestDetector(&FakeMetadataProvider{}, &FakeOSProvider{
 		Vars: map[string]string{
 			k8sServiceHostEnv: "foo",
 		},
 	})
 	platform := d.CloudPlatform()
+	assert.Equal(t, platform, GCE)
+}
+
+func TestCloudPlatformUnknown(t *testing.T) {
+	d := NewTestDetector(&FakeMetadataProvider{Err: fmt.Errorf("no metadata server")}, &FakeOSProvider{})
+	platform := d.CloudPlatform()
 	assert.Equal(t, platform, UnknownPlatform)
 }
 
diff --git a/detectors/gcp/utils_test.go b/detectors/gcp/utils_test.go
index 212c4418..28417725 100644
--- a/detectors/gcp/utils_test.go
+++ b/detectors/gcp/utils_test.go
@@ -14,6 +14,8 @@
 
 package gcp
 
+import "cloud.google.com/go/compute/metadata"
+
 func NewTestDetector(metadata *FakeMetadataProvider, os *FakeOSProvider) *Detector {
 	return &Detector{metadata: metadata, os: os}
 }
@@ -69,7 +71,11 @@ func (f *FakeMetadataProvider) InstanceAttributeValue(s string) (string, error)
 	if f.Err != nil {
 		return "", f.Err
 	}
-	return f.InstanceAttributes[s], nil
+	value, ok := f.InstanceAttributes[s]
+	if ok {
+		return value, nil
+	}
+	return "", metadata.NotDefinedError(s)
 }
 
 type FakeOSProvider struct {