Adding DeletePipeline API call and test

pipelines.go

@@ -229,3 +229,23 @@ func (s *PipelinesService) CancelPipelineBuild(pid interface{}, pipelineID int,
 
 	return p, resp, err
 }
+
+// DeletePipeline deletes an existing pipeline.
+//
+// GitLab API docs:
+// https://docs.gitlab.com/ce/api/pipelines.html#delete-a-pipeline
+func (s *PipelinesService) DeletePipeline(pid interface{}, pipelineID int, options ...OptionFunc) (*Response, error) {
+	project, err := parseID(pid)
+	if err != nil {
+		return nil, err
+	}
+
+	u := fmt.Sprintf("projects/%s/pipelines/%d", url.QueryEscape(project), pipelineID)
+
+	req, err := s.client.NewRequest("DELETE", u, nil, options)
+	if err != nil {
+		return nil, err
+	}
+
+	return s.client.Do(req, nil)
+}

pipelines_test.go

@@ -109,3 +109,19 @@ func TestCancelPipelineBuild(t *testing.T) {
 		t.Errorf("Pipelines.CancelPipelineBuild returned %+v, want %+v", pipeline, want)
 	}
 }
+
+func TestDeletePipeline(t *testing.T) {
+	mux, server, client := setup()
+	defer teardown(server)
+
+	mux.HandleFunc("/api/v4/projects/1/pipelines/5949167", func(w http.ResponseWriter, r *http.Request) {
+		testMethod(t, r, "DELETE")
+	})
+
+	_, err := client.Pipelines.DeletePipeline("1", 5949167)
+
+	if err != nil {
+		t.Errorf("Pipelines.DeletePipeline returned error: %v", err)
+	}
+
+}