Simplify Go Endpoints + Add Tests (#120)

This MR represents a major refactor of the Go codebase, as well as introducing tests for the handlers. The MR also introduces an endpoint to shutdown or restart the Go server, which may be useful for clients who want to refresh the state of the plugin after checking out branches. Finally, this MR adds a contributing document for users who want to make feature changes.

cmd/members_test.go

@@ -0,0 +1,52 @@
+package main
+
+import (
+	"errors"
+	"net/http"
+	"testing"
+
+	"github.com/xanzy/go-gitlab"
+)
+
+func listAllProjectMembers(pid interface{}, opt *gitlab.ListProjectMembersOptions, options ...gitlab.RequestOptionFunc) ([]*gitlab.ProjectMember, *gitlab.Response, error) {
+	return []*gitlab.ProjectMember{}, makeResponse(http.StatusOK), nil
+}
+
+func listAllProjectMembersErr(pid interface{}, opt *gitlab.ListProjectMembersOptions, options ...gitlab.RequestOptionFunc) ([]*gitlab.ProjectMember, *gitlab.Response, error) {
+	return nil, nil, errors.New("Some error from Gitlab")
+}
+
+func listAllProjectMembersNon200(pid interface{}, opt *gitlab.ListProjectMembersOptions, options ...gitlab.RequestOptionFunc) ([]*gitlab.ProjectMember, *gitlab.Response, error) {
+	return nil, makeResponse(http.StatusSeeOther), nil
+}
+
+func TestMembersHandler(t *testing.T) {
+	t.Run("Returns project members", func(t *testing.T) {
+		request := makeRequest(t, http.MethodGet, "/project/members", nil)
+		server, _ := createRouterAndApi(fakeClient{listAllProjectMembers: listAllProjectMembers})
+		data := serveRequest(t, server, request, ProjectMembersResponse{})
+		assert(t, data.SuccessResponse.Message, "Project members retrieved")
+		assert(t, data.SuccessResponse.Status, http.StatusOK)
+	})
+
+	t.Run("Disallows non-GET method", func(t *testing.T) {
+		request := makeRequest(t, http.MethodPost, "/project/members", nil)
+		server, _ := createRouterAndApi(fakeClient{listAllProjectMembers: listAllProjectMembers})
+		data := serveRequest(t, server, request, ErrorResponse{})
+		checkBadMethod(t, *data, http.MethodGet)
+	})
+
+	t.Run("Handles errors from Gitlab client", func(t *testing.T) {
+		request := makeRequest(t, http.MethodGet, "/project/members", nil)
+		server, _ := createRouterAndApi(fakeClient{listAllProjectMembers: listAllProjectMembersErr})
+		data := serveRequest(t, server, request, ErrorResponse{})
+		checkErrorFromGitlab(t, *data, "Could not retrieve project members")
+	})
+
+	t.Run("Handles non-200s from Gitlab client", func(t *testing.T) {
+		request := makeRequest(t, http.MethodGet, "/project/members", nil)
+		server, _ := createRouterAndApi(fakeClient{listAllProjectMembers: listAllProjectMembersNon200})
+		data := serveRequest(t, server, request, ErrorResponse{})
+		checkNon200(t, *data, "Could not retrieve project members", "/project/members")
+	})
+}