add a new method that allow to get an issue by id instead of iid

Author: Antoine Huret

issues.go

@@ -387,6 +387,26 @@ func (s *IssuesService) ListProjectIssues(pid interface{}, opt *ListProjectIssue
 	return i, resp, err
 }
 
+// GetIssueByID gets a single issue.
+//
+// GitLab API docs: https://docs.gitlab.com/ee/api/issues.html#single-issue
+func (s *IssuesService) GetIssueByID(issue int, options ...RequestOptionFunc) (*Issue, *Response, error) {
+	u := fmt.Sprintf("issues/%d", issue)
+
+	req, err := s.client.NewRequest(http.MethodGet, u, nil, options)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	i := new(Issue)
+	resp, err := s.client.Do(req, i)
+	if err != nil {
+		return nil, resp, err
+	}
+
+	return i, resp, err
+}
+
 // GetIssue gets a single project issue.
 //
 // GitLab API docs: https://docs.gitlab.com/ee/api/issues.html#single-project-issue

issues_test.go

@@ -52,6 +52,32 @@ func TestGetIssue(t *testing.T) {
 	}
 }
 
+func TestGetIssueByID(t *testing.T) {
+	mux, client := setup(t)
+
+	mux.HandleFunc("/api/v4/issues/5", func(w http.ResponseWriter, r *http.Request) {
+		testMethod(t, r, http.MethodGet)
+		fmt.Fprint(w, `{"id":5, "description": "This is test project", "author" : {"id" : 1, "name": "snehal"}, "assignees":[{"id":1}],"merge_requests_count": 1}`)
+	})
+
+	issue, _, err := client.Issues.GetIssueByID(5)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	want := &Issue{
+		ID:                5,
+		Description:       "This is test project",
+		Author:            &IssueAuthor{ID: 1, Name: "snehal"},
+		Assignees:         []*IssueAssignee{{ID: 1}},
+		MergeRequestCount: 1,
+	}
+
+	if !reflect.DeepEqual(want, issue) {
+		t.Errorf("Issues.GetIssueByID returned %+v, want %+v", issue, want)
+	}
+}
+
 func TestDeleteIssue(t *testing.T) {
 	mux, client := setup(t)