internal/lsp/regtest: clean-up and more error handling

Fix various things related to regtest execution:
 + Check the error from OpenFile in fake.Editor.GoToDefinition.
 + Add an error-checked wrapper to env for CloseBuffer.
 + Use env wrappers in TestDiagnosticClearingOnClose.
 + Use os.Executable to get the test binary path.
 + Add a -listen.timeout to the remote gopls process, so that it is
   cleaned up.

Updates golang/go#36879

Change-Id: I056ff50bdb611a78ad78e4f5e2a94a4f155cc9de
Reviewed-on: https://go-review.googlesource.com/c/tools/+/220902
Run-TryBot: Robert Findley <rfindley@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rebecca Stambler <rstambler@golang.org>

internal/lsp/fake/editor.go

@@ -348,7 +348,9 @@ func (e *Editor) GoToDefinition(ctx context.Context, path string, pos Pos) (stri
 	}
 	newPath := e.ws.URIToPath(resp[0].URI)
 	newPos := fromProtocolPosition(resp[0].Range.Start)
-	e.OpenFile(ctx, newPath)
+	if err := e.OpenFile(ctx, newPath); err != nil {
+		return "", Pos{}, fmt.Errorf("OpenFile: %v", err)
+	}
 	return newPath, newPos, nil
 }
 

internal/lsp/regtest/diagnostics_test.go

@@ -93,12 +93,11 @@ func TestDiagnosticClearingOnDelete(t *testing.T) {
 func TestDiagnosticClearingOnClose(t *testing.T) {
 	t.Parallel()
 	runner.Run(t, badPackage, func(ctx context.Context, t *testing.T, env *Env) {
-		env.E.CreateBuffer(env.ctx, "c.go", `package consts
+		env.CreateBuffer("c.go", `package consts
 
 const a = 3`)
 		env.Await(DiagnosticAt("a.go", 2, 6), DiagnosticAt("b.go", 2, 6), DiagnosticAt("c.go", 2, 6))
-		env.E.CloseBuffer(env.ctx, "c.go")
-
+		env.CloseBuffer("c.go")
 		env.Await(DiagnosticAt("a.go", 2, 6), DiagnosticAt("b.go", 2, 6), EmptyDiagnostics("c.go"))
 	})
 }

internal/lsp/regtest/env.go

@@ -110,7 +110,7 @@ func (r *Runner) getRemoteSocket(t *testing.T) string {
 		t.Fatalf("creating tempdir: %v", err)
 	}
 	socket := filepath.Join(r.socketDir, daemonFile)
-	args := []string{"serve", "-listen", "unix;" + socket}
+	args := []string{"serve", "-listen", "unix;" + socket, "-listen.timeout", "10s"}
 	cmd := exec.Command(r.goplsPath, args...)
 	cmd.Env = append(os.Environ(), runTestAsGoplsEnvvar+"=true")
 	var stderr bytes.Buffer
@@ -298,6 +298,14 @@ func (e *Env) CreateBuffer(name string, content string) {
 	}
 }
 
+// CloseBuffer closes an editor buffer, calling t.Fatal on any error.
+func (e *Env) CloseBuffer(name string) {
+	e.t.Helper()
+	if err := e.E.CloseBuffer(e.ctx, name); err != nil {
+		e.t.Fatal(err)
+	}
+}
+
 // EditBuffer applies edits to an editor buffer, calling t.Fatal on any error.
 func (e *Env) EditBuffer(name string, edits ...fake.Edit) {
 	e.t.Helper()

internal/lsp/regtest/reg_test.go

@@ -9,7 +9,6 @@ import (
 	"flag"
 	"fmt"
 	"os"
-	"path/filepath"
 	"testing"
 	"time"
 
@@ -39,7 +38,7 @@ func TestMain(m *testing.M) {
 		goplsPath := *goplsBinaryPath
 		if goplsPath == "" {
 			var err error
-			goplsPath, err = testBinaryPath()
+			goplsPath, err = os.Executable()
 			if err != nil {
 				panic(fmt.Sprintf("finding test binary path: %v", err))
 			}
@@ -52,18 +51,3 @@ func TestMain(m *testing.M) {
 	runner.Close()
 	os.Exit(code)
 }
-
-func testBinaryPath() (string, error) {
-	pth := os.Args[0]
-	if !filepath.IsAbs(pth) {
-		cwd, err := os.Getwd()
-		if err == nil {
-			return "", fmt.Errorf("os.Getwd: %v", err)
-		}
-		pth = filepath.Join(cwd, pth)
-	}
-	if _, err := os.Stat(pth); err != nil {
-		return "", fmt.Errorf("os.Stat: %v", err)
-	}
-	return pth, nil
-}