Refactor prSelectorForCurrentBranch and tests

Replace the git config argument in prSelectorForCurrentBranch with
the branchConfig it was used to fetch. The tests needed to be refactored
accordingly to support this change to the prSelectorForCurrentBranch API.
In addition, I've moved the test to a table test format so I can expand
the test coverage in the next commit.

pkg/cmd/pr/status/status.go

@@ -72,6 +72,7 @@ func NewCmdStatus(f *cmdutil.Factory, runF func(*StatusOptions) error) *cobra.Co
 }
 
 func statusRun(opts *StatusOptions) error {
+	ctx := context.Background()
 	httpClient, err := opts.HttpClient()
 	if err != nil {
 		return err
@@ -93,7 +94,8 @@ func statusRun(opts *StatusOptions) error {
 		}
 
 		remotes, _ := opts.Remotes()
-		currentPRNumber, currentPRHeadRef, err = prSelectorForCurrentBranch(opts.GitClient, baseRepo, currentBranch, remotes)
+		branchConfig, _ := opts.GitClient.ReadBranchConfig(ctx, currentBranch)
+		currentPRNumber, currentPRHeadRef, err = prSelectorForCurrentBranch(branchConfig, baseRepo, currentBranch, remotes)
 		if err != nil {
 			return fmt.Errorf("could not query for pull request for current branch: %w", err)
 		}
@@ -184,14 +186,15 @@ func statusRun(opts *StatusOptions) error {
 	return nil
 }
 
-func prSelectorForCurrentBranch(gitClient *git.Client, baseRepo ghrepo.Interface, prHeadRef string, rem ghContext.Remotes) (int, string, error) {
-	branchConfig, _ := gitClient.ReadBranchConfig(context.Background(), prHeadRef)
-
+func prSelectorForCurrentBranch(branchConfig git.BranchConfig, baseRepo ghrepo.Interface, prHeadRef string, rem ghContext.Remotes) (int, string, error) {
 	// the branch is configured to merge a special PR head ref
 	prHeadRE := regexp.MustCompile(`^refs/pull/(\d+)/head$`)
 	if m := prHeadRE.FindStringSubmatch(branchConfig.MergeRef); m != nil {
 		prNumber, err := strconv.Atoi(m[1])
-		return prNumber, prHeadRef, err
+		if err != nil {
+			return 0, "", err
+		}
+		return prNumber, prHeadRef, nil
 	}
 
 	var err error

pkg/cmd/pr/status/status_test.go

@@ -4,23 +4,23 @@ import (
 	"bytes"
 	"io"
 	"net/http"
+	"net/url"
 	"regexp"
 	"strings"
 	"testing"
 
-	"github.com/MakeNowJust/heredoc"
 	"github.com/cli/cli/v2/context"
 	"github.com/cli/cli/v2/git"
 	"github.com/cli/cli/v2/internal/config"
 	fd "github.com/cli/cli/v2/internal/featuredetection"
 	"github.com/cli/cli/v2/internal/gh"
 	"github.com/cli/cli/v2/internal/ghrepo"
-	"github.com/cli/cli/v2/internal/run"
 	"github.com/cli/cli/v2/pkg/cmdutil"
 	"github.com/cli/cli/v2/pkg/httpmock"
 	"github.com/cli/cli/v2/pkg/iostreams"
 	"github.com/cli/cli/v2/test"
 	"github.com/google/shlex"
+	"github.com/stretchr/testify/assert"
 )
 
 func runCommand(rt http.RoundTripper, branch string, isTTY bool, cli string) (*test.CmdOut, error) {
@@ -376,30 +376,48 @@ Requesting a code review from you
 }
 
 func Test_prSelectorForCurrentBranch(t *testing.T) {
-	rs, cleanup := run.Stub()
-	defer cleanup(t)
-
-	rs.Register(`git config --get-regexp \^branch\\.`, 0, heredoc.Doc(`
-		branch.Frederick888/main.remote git@github.com:Frederick888/playground.git
-		branch.Frederick888/main.merge refs/heads/main
-	`))
-
-	repo := ghrepo.NewWithHost("octocat", "playground", "github.com")
-	rem := context.Remotes{
-		&context.Remote{
-			Remote: &git.Remote{Name: "origin"},
-			Repo:   repo,
+	tests := []struct {
+		name         string
+		branchConfig git.BranchConfig
+		baseRepo     ghrepo.Interface
+		prHeadRef    string
+		remotes      context.Remotes
+		wantPrNumber int
+		wantSelector string
+		wantError    error
+	}{
+		{
+			name: "Branch merges from a remote specified by URL",
+			branchConfig: git.BranchConfig{
+				RemoteURL: &url.URL{
+					Scheme: "ssh",
+					User:   url.User("git"),
+					Host:   "github.com",
+					Path:   "Frederick888/playground.git",
+				},
+				MergeRef: "refs/heads/main",
+			},
+			baseRepo:  ghrepo.NewWithHost("octocat", "playground", "github.com"),
+			prHeadRef: "Frederick888/main",
+			remotes: context.Remotes{
+				&context.Remote{
+					Remote: &git.Remote{Name: "origin"},
+					Repo:   ghrepo.NewWithHost("octocat", "playground", "github.com"),
+				},
+			},
+			wantPrNumber: 0,
+			wantSelector: "Frederick888:main",
+			wantError:    nil,
 		},
 	}
-	gitClient := &git.Client{GitPath: "some/path/git"}
-	prNum, headRef, err := prSelectorForCurrentBranch(gitClient, repo, "Frederick888/main", rem)
-	if err != nil {
-		t.Fatalf("prSelectorForCurrentBranch error: %v", err)
-	}
-	if prNum != 0 {
-		t.Errorf("expected prNum to be 0, got %q", prNum)
-	}
-	if headRef != "Frederick888:main" {
-		t.Errorf("expected headRef to be \"Frederick888:main\", got %q", headRef)
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+
+			prNum, headRef, err := prSelectorForCurrentBranch(tt.branchConfig, tt.baseRepo, tt.prHeadRef, tt.remotes)
+			assert.Equal(t, tt.wantPrNumber, prNum)
+			assert.Equal(t, tt.wantSelector, headRef)
+			assert.Equal(t, tt.wantError, err)
+		})
 	}
 }