From c3c421acaf12027079009b6c68eb87b29a1bc048 Mon Sep 17 00:00:00 2001
From: Orlando Valverde <4467518+septum@users.noreply.github.com>
Date: Wed, 21 Aug 2024 11:05:55 -0600
Subject: [PATCH] backend: Update GitHub Service to get a PR (#3095)

---
 backend/mock/service/githubmock/githubmock.go |  6 ++
 backend/service/github/github.go              |  9 +++
 backend/service/github/github_test.go         | 59 +++++++++++++++++++
 backend/service/github/iface.go               |  2 +
 4 files changed, 76 insertions(+)

diff --git a/backend/mock/service/githubmock/githubmock.go b/backend/mock/service/githubmock/githubmock.go
index e0b87d792b..d01dae344d 100644
--- a/backend/mock/service/githubmock/githubmock.go
+++ b/backend/mock/service/githubmock/githubmock.go
@@ -80,6 +80,12 @@ func (s svc) ListPullRequestsWithCommit(ctx context.Context, ref *github.RemoteR
 	}, nil
 }
 
+func (s svc) GetPullRequest(ctx context.Context, owner, repo string, number int) (*githubv3.PullRequest, error) {
+	return &githubv3.PullRequest{
+		Number: githubv3.Int(4242),
+	}, nil
+}
+
 func (s svc) GetOrgMembership(ctx context.Context, user, org string) (*githubv3.Membership, error) {
 	role := "member"
 	return &githubv3.Membership{Role: &role}, nil
diff --git a/backend/service/github/github.go b/backend/service/github/github.go
index 85dc948c4d..a96286dd32 100644
--- a/backend/service/github/github.go
+++ b/backend/service/github/github.go
@@ -125,6 +125,7 @@ type Client interface {
 	ListPullRequestsWithCommit(ctx context.Context, ref *RemoteRef, sha string, opts *githubv3.ListOptions) ([]*PullRequestInfo, error)
 	GetOrgMembership(ctx context.Context, user, org string) (*githubv3.Membership, error)
 	GetUser(ctx context.Context, username string) (*githubv3.User, error)
+	GetPullRequest(ctx context.Context, owner, repo string, number int) (*githubv3.PullRequest, error)
 }
 
 // This func can be used to create comments for PRs or Issues
@@ -299,6 +300,14 @@ func (s *svc) ListPullRequestsWithCommit(ctx context.Context, ref *RemoteRef, sh
 	return prInfos, nil
 }
 
+func (s *svc) GetPullRequest(ctx context.Context, owner, repo string, number int) (*githubv3.PullRequest, error) {
+	pr, _, err := s.rest.PullRequests.Get(ctx, owner, repo, number)
+	if err != nil {
+		return nil, err
+	}
+	return pr, nil
+}
+
 type CreateBranchRequest struct {
 	// The base for the new branch.
 	Ref *RemoteRef
diff --git a/backend/service/github/github_test.go b/backend/service/github/github_test.go
index 256a806d9b..7803e884e6 100644
--- a/backend/service/github/github_test.go
+++ b/backend/service/github/github_test.go
@@ -896,6 +896,13 @@ func (m *mockPullRequests) Create(ctx context.Context, owner string, repo string
 	return &githubv3.PullRequest{}, &githubv3.Response{}, nil
 }
 
+func (m *mockPullRequests) Get(ctx context.Context, owner, repo string, number int) (*githubv3.PullRequest, *githubv3.Response, error) {
+	if m.generalError == true {
+		return nil, nil, errors.New(problem)
+	}
+	return &githubv3.PullRequest{}, &githubv3.Response{}, nil
+}
+
 // Mock of ListPullRequestsWithCommit API
 func (m *mockPullRequests) ListPullRequestsWithCommit(ctx context.Context, owner, repo, sha string, opts *githubv3.ListOptions) ([]*githubv3.PullRequest, *githubv3.Response, error) {
 	if m.generalError {
@@ -985,6 +992,58 @@ func TestListPullRequestsWithCommit(t *testing.T) {
 	}
 }
 
+var getPullRequestTests = []struct {
+	name        string
+	errorText   string
+	mockPullReq *mockPullRequests
+	repoOwner   string
+	repoName    string
+	prNumber    int
+}{
+	{
+		name:        "happy path",
+		mockPullReq: &mockPullRequests{},
+		repoOwner:   "my-org",
+		repoName:    "my-repo",
+		prNumber:    4242,
+	},
+	{
+		name:        "v3 client error",
+		mockPullReq: &mockPullRequests{generalError: true},
+		errorText:   "we've had a problem",
+		repoOwner:   "my-org",
+		repoName:    "my-repo",
+		prNumber:    4242,
+	},
+}
+
+func TestGetPullRequest(t *testing.T) {
+	for _, tt := range getPullRequestTests {
+		tt := tt
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+
+			s := &svc{rest: v3client{
+				PullRequests: tt.mockPullReq,
+			}}
+
+			resp, err := s.GetPullRequest(
+				context.Background(),
+				tt.repoOwner,
+				tt.repoName,
+				tt.prNumber)
+
+			if tt.errorText != "" {
+				assert.Error(t, err)
+				assert.Contains(t, err.Error(), tt.errorText)
+			} else {
+				assert.NoError(t, err)
+				assert.Equal(t, tt.mockPullReq.actualNumber, resp.GetNumber())
+			}
+		})
+	}
+}
+
 func TestNewService(t *testing.T) {
 	cfg := &githubconfigv1.Config{}
 	_, err := newService(cfg, tally.NoopScope, zap.NewNop())
diff --git a/backend/service/github/iface.go b/backend/service/github/iface.go
index 7c3c45bd9e..487a4144f5 100644
--- a/backend/service/github/iface.go
+++ b/backend/service/github/iface.go
@@ -35,6 +35,8 @@ type v3pullrequests interface {
 	Create(ctx context.Context, owner string, repo string, pull *githubv3.NewPullRequest) (*githubv3.PullRequest, *githubv3.Response, error)
 	// ListPullRequestsWithCommit returns pull requests associated with a commit SHA.
 	ListPullRequestsWithCommit(ctx context.Context, owner, repo, sha string, opts *githubv3.ListOptions) ([]*githubv3.PullRequest, *githubv3.Response, error)
+	// GetPullRequest returns a single pull request specified by the PR number
+	Get(ctx context.Context, owner, repo string, number int) (*githubv3.PullRequest, *githubv3.Response, error)
 }
 
 type v4client interface {