Update changed request, add test and test result.

commits.go

@@ -552,7 +552,7 @@ func (s *CommitsService) RevertCommit(pid interface{}, sha string, opt *RevertCo
 //
 // GitLab API docs: https://docs.gitlab.com/ee/api/commits.html#get-gpg-signature-of-a-commit
 type GPGSubKey struct {
-	KeyID sql.NullInt64
+	sql.NullInt64
 }
 
 // GPGSignature represents a Gitlab commit's GPG Signature.
@@ -575,19 +575,19 @@ func (s *CommitsService) GetGPGSiganature(pid interface{}, sha string, options .
 	if err != nil {
 		return nil, nil, err
 	}
+	u := fmt.Sprintf("projects/%s/repository/commits/%s/signature", pathEscape(project), sha)
 
-	url := fmt.Sprintf("projects/%s/repository/commits/%s/signature", pathEscape(project), sha)
-	req, err := s.client.NewRequest("GET", url, nil, options)
+	req, err := s.client.NewRequest("GET", u, nil, options)
 	if err != nil {
 		return nil, nil, err
 	}
 
-	var signature *GPGSignature
-	resp, err := s.client.Do(req, &signature)
+	sig := new(GPGSignature)
+	resp, err := s.client.Do(req, &sig)
 
 	if err != nil {
 		return nil, resp, err
 	}
 
-	return signature, resp, err
+	return sig, resp, err
 }

commits_test.go

@@ -174,3 +174,29 @@ func TestRevertCommit_WithOptions(t *testing.T) {
 
 	assert.Equal(t, want, commit)
 }
+
+func TestGetGPGSignature(t *testing.T) {
+	mux, server, client := setup()
+	defer teardown(server)
+
+	mux.HandleFunc("/api/v4/projects/1/repository/commits/b0b3a907f41409829b307a28b82fdbd552ee5a27/signature", func(w http.ResponseWriter, r *http.Request) {
+		testMethod(t, r, "GET")
+		mustWriteHTTPResponse(t, w, "testdata/get_signature.json")
+	})
+
+	sig, resp, err := client.Commits.GetGPGSiganature("1", "b0b3a907f41409829b307a28b82fdbd552ee5a27", nil)
+	if err != nil {
+		t.Fatalf("Commits.GetGPGSignature returned error: %v, response: %v", err, resp)
+	}
+
+	want := &GPGSignature{
+		KeyID:              7977,
+		KeyPrimaryKeyID:    "627C5F589F467F17",
+		KeyUserName:        "Dmitriy Zaporozhets",
+		KeyUserEmail:       "dmitriy.zaporozhets@gmail.com",
+		VerificationStatus: "verified",
+		KeySubkeyID:        nil,
+	}
+
+	assert.Equal(t, want, sig)
+}

testdata/get_signature.json

+{
+    "gpg_key_id": 7977,
+    "gpg_key_primary_keyid": "627C5F589F467F17",
+    "gpg_key_user_name": "Dmitriy Zaporozhets",
+    "gpg_key_user_email": "dmitriy.zaporozhets@gmail.com",
+    "verification_status": "verified",
+    "gpg_key_subkey_id": null
+}
\ No newline at end of file