internal/lsp/lsp_test.go - tools - Git at Google

 // Copyright 2018 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.

 package lsp

 import (
 	"bytes"
 	"context"
 	"fmt"
 	"go/ast"
 	"go/parser"
 	"go/token"
 	"os/exec"
 	"path/filepath"
 	"strings"
 	"testing"

 	"golang.org/x/tools/go/packages/packagestest"
 	"golang.org/x/tools/internal/lsp/cache"
 	"golang.org/x/tools/internal/lsp/diff"
 	"golang.org/x/tools/internal/lsp/protocol"
 	"golang.org/x/tools/internal/lsp/source"
 )

 // TODO(rstambler): Remove this once Go 1.12 is released as we end support for
 // versions of Go <= 1.10.
 var goVersion111 = true

 func TestLSP(t *testing.T) {
 	packagestest.TestAll(t, testLSP)
 }

 func testLSP(t *testing.T, exporter packagestest.Exporter) {
 	const dir = "testdata"

 	// We hardcode the expected number of test cases to ensure that all tests
 	// are being executed. If a test is added, this number must be changed.
 	const expectedCompletionsCount = 63
 	const expectedDiagnosticsCount = 17
 	const expectedFormatCount = 4
 	const expectedDefinitionsCount = 16
 	const expectedTypeDefinitionsCount = 2

 	files := packagestest.MustCopyFileTree(dir)
 	for fragment, operation := range files {
 		if trimmed := strings.TrimSuffix(fragment, ".in"); trimmed != fragment {
 			delete(files, fragment)
 			files[trimmed] = operation
 		}
 	}
 	modules := []packagestest.Module{
 		{
 			Name:  "golang.org/x/tools/internal/lsp",
 			Files: files,
 		},
 	}
 	exported := packagestest.Export(t, exporter, modules)
 	defer exported.Cleanup()

 	// Merge the exported.Config with the view.Config.
 	cfg := *exported.Config
 	cfg.Fset = token.NewFileSet()
 	cfg.Context = context.Background()
 	cfg.ParseFile = func(fset *token.FileSet, filename string, src []byte) (*ast.File, error) {
 		return parser.ParseFile(fset, filename, src, parser.AllErrors|parser.ParseComments)
 	}

 	s := &server{
 		view: cache.NewView(&cfg),
 	}
 	// Do a first pass to collect special markers for completion.
 	if err := exported.Expect(map[string]interface{}{
 		"item": func(name string, r packagestest.Range, _, _ string) {
 			exported.Mark(name, r)
 		},
 	}); err != nil {
 		t.Fatal(err)
 	}

 	expectedDiagnostics := make(diagnostics)
 	completionItems := make(completionItems)
 	expectedCompletions := make(completions)
 	expectedFormat := make(formats)
 	expectedDefinitions := make(definitions)
 	expectedTypeDefinitions := make(definitions)

 	// Collect any data that needs to be used by subsequent tests.
 	if err := exported.Expect(map[string]interface{}{
 		"diag":     expectedDiagnostics.collect,
 		"item":     completionItems.collect,
 		"complete": expectedCompletions.collect,
 		"format":   expectedFormat.collect,
 		"godef":    expectedDefinitions.collect,
 		"typdef":   expectedTypeDefinitions.collect,
 	}); err != nil {
 		t.Fatal(err)
 	}

 	t.Run("Completion", func(t *testing.T) {
 		t.Helper()
 		if goVersion111 { // TODO(rstambler): Remove this when we no longer support Go 1.10.
 			if len(expectedCompletions) != expectedCompletionsCount {
 				t.Errorf("got %v completions expected %v", len(expectedCompletions), expectedCompletionsCount)
 			}
 		}
 		expectedCompletions.test(t, exported, s, completionItems)
 	})

 	t.Run("Diagnostics", func(t *testing.T) {
 		t.Helper()
 		diagnosticsCount := expectedDiagnostics.test(t, s.view)
 		if goVersion111 { // TODO(rstambler): Remove this when we no longer support Go 1.10.
 			if diagnosticsCount != expectedDiagnosticsCount {
 				t.Errorf("got %v diagnostics expected %v", diagnosticsCount, expectedDiagnosticsCount)
 			}
 		}
 	})

 	t.Run("Format", func(t *testing.T) {
 		t.Helper()
 		if goVersion111 { // TODO(rstambler): Remove this when we no longer support Go 1.10.
 			if len(expectedFormat) != expectedFormatCount {
 				t.Errorf("got %v formats expected %v", len(expectedFormat), expectedFormatCount)
 			}
 		}
 		expectedFormat.test(t, s)
 	})

 	t.Run("Definitions", func(t *testing.T) {
 		t.Helper()
 		if goVersion111 { // TODO(rstambler): Remove this when we no longer support Go 1.10.
 			if len(expectedDefinitions) != expectedDefinitionsCount {
 				t.Errorf("got %v definitions expected %v", len(expectedDefinitions), expectedDefinitionsCount)
 			}
 		}
 		expectedDefinitions.test(t, s, false)
 	})

 	t.Run("TypeDefinitions", func(t *testing.T) {
 		t.Helper()
 		if goVersion111 { // TODO(rstambler): Remove this when we no longer support Go 1.10.
 			if len(expectedTypeDefinitions) != expectedTypeDefinitionsCount {
 				t.Errorf("got %v type definitions expected %v", len(expectedTypeDefinitions), expectedTypeDefinitionsCount)
 			}
 		}
 		expectedTypeDefinitions.test(t, s, true)
 	})
 }

 type diagnostics map[string][]protocol.Diagnostic
 type completionItems map[token.Pos]*protocol.CompletionItem
 type completions map[token.Position][]token.Pos
 type formats map[string]string
 type definitions map[protocol.Location]protocol.Location

 func (d diagnostics) test(t *testing.T, v source.View) int {
 	count := 0
 	ctx := context.Background()
 	for filename, want := range d {
 		sourceDiagnostics, err := source.Diagnostics(context.Background(), v, source.ToURI(filename))
 		if err != nil {
 			t.Fatal(err)
 		}
 		got := toProtocolDiagnostics(ctx, v, sourceDiagnostics[filename])
 		sorted(got)
 		if diff := diffDiagnostics(filename, want, got); diff != "" {
 			t.Error(diff)
 		}
 		count += len(want)
 	}
 	return count
 }

 func (d diagnostics) collect(fset *token.FileSet, rng packagestest.Range, msgSource, msg string) {
 	f := fset.File(rng.Start)
 	if _, ok := d[f.Name()]; !ok {
 		d[f.Name()] = []protocol.Diagnostic{}
 	}
 	// If a file has an empty diagnostic message, return. This allows us to
 	// avoid testing diagnostics in files that may have a lot of them.
 	if msg == "" {
 		return
 	}
 	want := protocol.Diagnostic{
 		Range:    toProtocolRange(f, source.Range(rng)),
 		Severity: protocol.SeverityError,
 		Source:   msgSource,
 		Message:  msg,
 	}
 	d[f.Name()] = append(d[f.Name()], want)
 }

 // diffDiagnostics prints the diff between expected and actual diagnostics test
 // results.
 func diffDiagnostics(filename string, want, got []protocol.Diagnostic) string {
 	if len(got) != len(want) {
 		goto Failed
 	}
 	for i, w := range want {
 		g := got[i]
 		if w.Message != g.Message {
 			goto Failed
 		}
 		if w.Range.Start != g.Range.Start {
 			goto Failed
 		}
 		// Special case for diagnostics on parse errors.
 		if strings.Contains(filename, "noparse") {
 			if g.Range.Start != g.Range.End || w.Range.Start != g.Range.End {
 				goto Failed
 			}
 		} else if g.Range.End != g.Range.Start { // Accept any 'want' range if the diagnostic returns a zero-length range.
 			if w.Range.End != g.Range.End {
 				goto Failed
 			}
 		}
 		if w.Severity != g.Severity {
 			goto Failed
 		}
 		if w.Source != g.Source {
 			goto Failed
 		}
 	}
 	return ""
 Failed:
 	msg := &bytes.Buffer{}
 	fmt.Fprintf(msg, "diagnostics failed for %s:\nexpected:\n", filename)
 	for _, d := range want {
 		fmt.Fprintf(msg, "  %v\n", d)
 	}
 	fmt.Fprintf(msg, "got:\n")
 	for _, d := range got {
 		fmt.Fprintf(msg, "  %v\n", d)
 	}
 	return msg.String()
 }

 func (c completions) test(t *testing.T, exported *packagestest.Exported, s *server, items completionItems) {
 	for src, itemList := range c {
 		var want []protocol.CompletionItem
 		for _, pos := range itemList {
 			want = append(want, *items[pos])
 		}
 		list, err := s.Completion(context.Background(), &protocol.CompletionParams{
 			TextDocumentPositionParams: protocol.TextDocumentPositionParams{
 				TextDocument: protocol.TextDocumentIdentifier{
 					URI: protocol.DocumentURI(source.ToURI(src.Filename)),
 				},
 				Position: protocol.Position{
 					Line:      float64(src.Line - 1),
 					Character: float64(src.Column - 1),
 				},
 			},
 		})
 		if err != nil {
 			t.Fatal(err)
 		}
 		wantBuiltins := strings.Contains(src.Filename, "builtins")
 		var got []protocol.CompletionItem
 		for _, item := range list.Items {
 			if !wantBuiltins && isBuiltin(item) {
 				continue
 			}
 			got = append(got, item)
 		}
 		if err != nil {
 			t.Fatalf("completion failed for %s:%v:%v: %v", filepath.Base(src.Filename), src.Line, src.Column, err)
 		}
 		if diff := diffCompletionItems(t, src, want, got); diff != "" {
 			t.Errorf(diff)
 		}
 	}
 }

 func isBuiltin(item protocol.CompletionItem) bool {
 	// If a type has no detail, it is a builtin type.
 	if item.Detail == "" && item.Kind == float64(protocol.TypeParameterCompletion) {
 		return true
 	}
 	// Remaining builtin constants, variables, interfaces, and functions.
 	trimmed := item.Label
 	if i := strings.Index(trimmed, "("); i >= 0 {
 		trimmed = trimmed[:i]
 	}
 	switch trimmed {
 	case "append", "cap", "close", "complex", "copy", "delete",
 		"error", "false", "imag", "iota", "len", "make", "new",
 		"nil", "panic", "print", "println", "real", "recover", "true":
 		return true
 	}
 	return false
 }

 func (c completions) collect(src token.Position, expected []token.Pos) {
 	c[src] = expected
 }

 func (i completionItems) collect(pos token.Pos, label, detail, kind string) {
 	var k protocol.CompletionItemKind
 	switch kind {
 	case "struct":
 		k = protocol.StructCompletion
 	case "func":
 		k = protocol.FunctionCompletion
 	case "var":
 		k = protocol.VariableCompletion
 	case "type":
 		k = protocol.TypeParameterCompletion
 	case "field":
 		k = protocol.FieldCompletion
 	case "interface":
 		k = protocol.InterfaceCompletion
 	case "const":
 		k = protocol.ConstantCompletion
 	case "method":
 		k = protocol.MethodCompletion
 	case "package":
 		k = protocol.ModuleCompletion
 	}
 	i[pos] = &protocol.CompletionItem{
 		Label:  label,
 		Detail: detail,
 		Kind:   float64(k),
 	}
 }

 // diffCompletionItems prints the diff between expected and actual completion
 // test results.
 func diffCompletionItems(t *testing.T, pos token.Position, want, got []protocol.CompletionItem) string {
 	if len(got) != len(want) {
 		goto Failed
 	}
 	for i, w := range want {
 		g := got[i]
 		if w.Label != g.Label {
 			goto Failed
 		}
 		if w.Detail != g.Detail {
 			goto Failed
 		}
 		if w.Kind != g.Kind {
 			goto Failed
 		}
 	}
 	return ""
 Failed:
 	msg := &bytes.Buffer{}
 	fmt.Fprintf(msg, "completion failed for %s:%v:%v:\nexpected:\n", filepath.Base(pos.Filename), pos.Line, pos.Column)
 	for _, d := range want {
 		fmt.Fprintf(msg, "  %v\n", d)
 	}
 	fmt.Fprintf(msg, "got:\n")
 	for _, d := range got {
 		fmt.Fprintf(msg, "  %v\n", d)
 	}
 	return msg.String()
 }

 func (f formats) test(t *testing.T, s *server) {
 	for filename, gofmted := range f {
 		edits, err := s.Formatting(context.Background(), &protocol.DocumentFormattingParams{
 			TextDocument: protocol.TextDocumentIdentifier{
 				URI: protocol.DocumentURI(source.ToURI(filename)),
 			},
 		})
 		if err != nil {
 			if gofmted != "" {
 				t.Error(err)
 			}
 			continue
 		}
 		f, err := s.view.GetFile(context.Background(), source.ToURI(filename))
 		if err != nil {
 			t.Error(err)
 		}
 		original, err := f.Read()
 		if err != nil {
 			t.Error(err)
 		}
 		var ops []*diff.Op
 		for _, edit := range edits {
 			start := int(edit.Range.Start.Line)
 			end := int(edit.Range.End.Line)
 			if start == end && edit.Range.End.Character > 1 {
 				end++
 			}
 			if edit.NewText == "" { // deletion
 				ops = append(ops, &diff.Op{
 					Kind: diff.Delete,
 					I1:   start,
 					I2:   end,
 				})
 			} else if edit.Range.Start == edit.Range.End { // insertion
 				ops = append(ops, &diff.Op{
 					Kind:    diff.Insert,
 					Content: edit.NewText,
 					I1:      start,
 					I2:      end,
 				})
 			}
 		}
 		split := strings.SplitAfter(string(original), "\n")
 		got := strings.Join(diff.ApplyEdits(split, ops), "")
 		if gofmted != got {
 			t.Errorf("format failed for %s: expected '%v', got '%v'", filename, gofmted, got)
 		}
 	}
 }

 func (f formats) collect(pos token.Position) {
 	cmd := exec.Command("gofmt", pos.Filename)
 	stdout := bytes.NewBuffer(nil)
 	cmd.Stdout = stdout
 	cmd.Run() // ignore error, sometimes we have intentionally ungofmt-able files
 	f[pos.Filename] = stdout.String()
 }

 func (d definitions) test(t *testing.T, s *server, typ bool) {
 	for src, target := range d {
 		params := &protocol.TextDocumentPositionParams{
 			TextDocument: protocol.TextDocumentIdentifier{
 				URI: src.URI,
 			},
 			Position: src.Range.Start,
 		}
 		var locs []protocol.Location
 		var err error
 		if typ {
 			locs, err = s.TypeDefinition(context.Background(), params)
 		} else {
 			locs, err = s.Definition(context.Background(), params)
 		}
 		if err != nil {
 			t.Fatalf("failed for %s: %v", src, err)
 		}
 		if len(locs) != 1 {
 			t.Errorf("got %d locations for definition, expected 1", len(locs))
 		}
 		if locs[0] != target {
 			t.Errorf("for %v got %v want %v", src, locs[0], target)
 		}
 	}
 }

 func (d definitions) collect(fset *token.FileSet, src, target packagestest.Range) {
 	loc := toProtocolLocation(fset, source.Range(src))
 	d[loc] = toProtocolLocation(fset, source.Range(target))
 }
	// Copyright 2018 The Go Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style
	// license that can be found in the LICENSE file.

	package lsp

	import (
	"bytes"
	"context"
	"fmt"
	"go/ast"
	"go/parser"
	"go/token"
	"os/exec"
	"path/filepath"
	"strings"
	"testing"

	"golang.org/x/tools/go/packages/packagestest"
	"golang.org/x/tools/internal/lsp/cache"
	"golang.org/x/tools/internal/lsp/diff"
	"golang.org/x/tools/internal/lsp/protocol"
	"golang.org/x/tools/internal/lsp/source"
	)

	// TODO(rstambler): Remove this once Go 1.12 is released as we end support for
	// versions of Go <= 1.10.
	var goVersion111 = true

	func TestLSP(t *testing.T) {
	packagestest.TestAll(t, testLSP)
	}

	func testLSP(t *testing.T, exporter packagestest.Exporter) {
	const dir = "testdata"

	// We hardcode the expected number of test cases to ensure that all tests
	// are being executed. If a test is added, this number must be changed.
	const expectedCompletionsCount = 63
	const expectedDiagnosticsCount = 17
	const expectedFormatCount = 4
	const expectedDefinitionsCount = 16
	const expectedTypeDefinitionsCount = 2

	files := packagestest.MustCopyFileTree(dir)
	for fragment, operation := range files {
	if trimmed := strings.TrimSuffix(fragment, ".in"); trimmed != fragment {
	delete(files, fragment)
	files[trimmed] = operation
	}
	}
	modules := []packagestest.Module{
	{
	Name: "golang.org/x/tools/internal/lsp",
	Files: files,
	},
	}
	exported := packagestest.Export(t, exporter, modules)
	defer exported.Cleanup()

	// Merge the exported.Config with the view.Config.
	cfg := *exported.Config
	cfg.Fset = token.NewFileSet()
	cfg.Context = context.Background()
	cfg.ParseFile = func(fset token.FileSet, filename string, src []byte) (ast.File, error) {
	return parser.ParseFile(fset, filename, src, parser.AllErrors\|parser.ParseComments)
	}

	s := &server{
	view: cache.NewView(&cfg),
	}
	// Do a first pass to collect special markers for completion.
	if err := exported.Expect(map[string]interface{}{
	"item": func(name string, r packagestest.Range, _, _ string) {
	exported.Mark(name, r)
	},
	}); err != nil {
	t.Fatal(err)
	}

	expectedDiagnostics := make(diagnostics)
	completionItems := make(completionItems)
	expectedCompletions := make(completions)
	expectedFormat := make(formats)
	expectedDefinitions := make(definitions)
	expectedTypeDefinitions := make(definitions)

	// Collect any data that needs to be used by subsequent tests.
	if err := exported.Expect(map[string]interface{}{
	"diag": expectedDiagnostics.collect,
	"item": completionItems.collect,
	"complete": expectedCompletions.collect,
	"format": expectedFormat.collect,
	"godef": expectedDefinitions.collect,
	"typdef": expectedTypeDefinitions.collect,
	}); err != nil {
	t.Fatal(err)
	}

	t.Run("Completion", func(t *testing.T) {
	t.Helper()
	if goVersion111 { // TODO(rstambler): Remove this when we no longer support Go 1.10.
	if len(expectedCompletions) != expectedCompletionsCount {
	t.Errorf("got %v completions expected %v", len(expectedCompletions), expectedCompletionsCount)
	}
	}
	expectedCompletions.test(t, exported, s, completionItems)
	})

	t.Run("Diagnostics", func(t *testing.T) {
	t.Helper()
	diagnosticsCount := expectedDiagnostics.test(t, s.view)
	if goVersion111 { // TODO(rstambler): Remove this when we no longer support Go 1.10.
	if diagnosticsCount != expectedDiagnosticsCount {
	t.Errorf("got %v diagnostics expected %v", diagnosticsCount, expectedDiagnosticsCount)
	}
	}
	})

	t.Run("Format", func(t *testing.T) {
	t.Helper()
	if goVersion111 { // TODO(rstambler): Remove this when we no longer support Go 1.10.
	if len(expectedFormat) != expectedFormatCount {
	t.Errorf("got %v formats expected %v", len(expectedFormat), expectedFormatCount)
	}
	}
	expectedFormat.test(t, s)
	})

	t.Run("Definitions", func(t *testing.T) {
	t.Helper()
	if goVersion111 { // TODO(rstambler): Remove this when we no longer support Go 1.10.
	if len(expectedDefinitions) != expectedDefinitionsCount {
	t.Errorf("got %v definitions expected %v", len(expectedDefinitions), expectedDefinitionsCount)
	}
	}
	expectedDefinitions.test(t, s, false)
	})

	t.Run("TypeDefinitions", func(t *testing.T) {
	t.Helper()
	if goVersion111 { // TODO(rstambler): Remove this when we no longer support Go 1.10.
	if len(expectedTypeDefinitions) != expectedTypeDefinitionsCount {
	t.Errorf("got %v type definitions expected %v", len(expectedTypeDefinitions), expectedTypeDefinitionsCount)
	}
	}
	expectedTypeDefinitions.test(t, s, true)
	})
	}

	type diagnostics map[string][]protocol.Diagnostic
	type completionItems map[token.Pos]*protocol.CompletionItem
	type completions map[token.Position][]token.Pos
	type formats map[string]string
	type definitions map[protocol.Location]protocol.Location

	func (d diagnostics) test(t *testing.T, v source.View) int {
	count := 0
	ctx := context.Background()
	for filename, want := range d {
	sourceDiagnostics, err := source.Diagnostics(context.Background(), v, source.ToURI(filename))
	if err != nil {
	t.Fatal(err)
	}
	got := toProtocolDiagnostics(ctx, v, sourceDiagnostics[filename])
	sorted(got)
	if diff := diffDiagnostics(filename, want, got); diff != "" {
	t.Error(diff)
	}
	count += len(want)
	}
	return count
	}

	func (d diagnostics) collect(fset *token.FileSet, rng packagestest.Range, msgSource, msg string) {
	f := fset.File(rng.Start)
	if _, ok := d[f.Name()]; !ok {
	d[f.Name()] = []protocol.Diagnostic{}
	}
	// If a file has an empty diagnostic message, return. This allows us to
	// avoid testing diagnostics in files that may have a lot of them.
	if msg == "" {
	return
	}
	want := protocol.Diagnostic{
	Range: toProtocolRange(f, source.Range(rng)),
	Severity: protocol.SeverityError,
	Source: msgSource,
	Message: msg,
	}
	d[f.Name()] = append(d[f.Name()], want)
	}

	// diffDiagnostics prints the diff between expected and actual diagnostics test
	// results.
	func diffDiagnostics(filename string, want, got []protocol.Diagnostic) string {
	if len(got) != len(want) {
	goto Failed
	}
	for i, w := range want {
	g := got[i]
	if w.Message != g.Message {
	goto Failed
	}
	if w.Range.Start != g.Range.Start {
	goto Failed
	}
	// Special case for diagnostics on parse errors.
	if strings.Contains(filename, "noparse") {
	if g.Range.Start != g.Range.End \|\| w.Range.Start != g.Range.End {
	goto Failed
	}
	} else if g.Range.End != g.Range.Start { // Accept any 'want' range if the diagnostic returns a zero-length range.
	if w.Range.End != g.Range.End {
	goto Failed
	}
	}
	if w.Severity != g.Severity {
	goto Failed
	}
	if w.Source != g.Source {
	goto Failed
	}
	}
	return ""
	Failed:
	msg := &bytes.Buffer{}
	fmt.Fprintf(msg, "diagnostics failed for %s:\nexpected:\n", filename)
	for _, d := range want {
	fmt.Fprintf(msg, " %v\n", d)
	}
	fmt.Fprintf(msg, "got:\n")
	for _, d := range got {
	fmt.Fprintf(msg, " %v\n", d)
	}
	return msg.String()
	}

	func (c completions) test(t testing.T, exported packagestest.Exported, s *server, items completionItems) {
	for src, itemList := range c {
	var want []protocol.CompletionItem
	for _, pos := range itemList {
	want = append(want, *items[pos])
	}
	list, err := s.Completion(context.Background(), &protocol.CompletionParams{
	TextDocumentPositionParams: protocol.TextDocumentPositionParams{
	TextDocument: protocol.TextDocumentIdentifier{
	URI: protocol.DocumentURI(source.ToURI(src.Filename)),
	},
	Position: protocol.Position{
	Line: float64(src.Line - 1),
	Character: float64(src.Column - 1),
	},
	},
	})
	if err != nil {
	t.Fatal(err)
	}
	wantBuiltins := strings.Contains(src.Filename, "builtins")
	var got []protocol.CompletionItem
	for _, item := range list.Items {
	if !wantBuiltins && isBuiltin(item) {
	continue
	}
	got = append(got, item)
	}
	if err != nil {
	t.Fatalf("completion failed for %s:%v:%v: %v", filepath.Base(src.Filename), src.Line, src.Column, err)
	}
	if diff := diffCompletionItems(t, src, want, got); diff != "" {
	t.Errorf(diff)
	}
	}
	}

	func isBuiltin(item protocol.CompletionItem) bool {
	// If a type has no detail, it is a builtin type.
	if item.Detail == "" && item.Kind == float64(protocol.TypeParameterCompletion) {
	return true
	}
	// Remaining builtin constants, variables, interfaces, and functions.
	trimmed := item.Label
	if i := strings.Index(trimmed, "("); i >= 0 {
	trimmed = trimmed[:i]
	}
	switch trimmed {
	case "append", "cap", "close", "complex", "copy", "delete",
	"error", "false", "imag", "iota", "len", "make", "new",
	"nil", "panic", "print", "println", "real", "recover", "true":
	return true
	}
	return false
	}

	func (c completions) collect(src token.Position, expected []token.Pos) {
	c[src] = expected
	}

	func (i completionItems) collect(pos token.Pos, label, detail, kind string) {
	var k protocol.CompletionItemKind
	switch kind {
	case "struct":
	k = protocol.StructCompletion
	case "func":
	k = protocol.FunctionCompletion
	case "var":
	k = protocol.VariableCompletion
	case "type":
	k = protocol.TypeParameterCompletion
	case "field":
	k = protocol.FieldCompletion
	case "interface":
	k = protocol.InterfaceCompletion
	case "const":
	k = protocol.ConstantCompletion
	case "method":
	k = protocol.MethodCompletion
	case "package":
	k = protocol.ModuleCompletion
	}
	i[pos] = &protocol.CompletionItem{
	Label: label,
	Detail: detail,
	Kind: float64(k),
	}
	}

	// diffCompletionItems prints the diff between expected and actual completion
	// test results.
	func diffCompletionItems(t *testing.T, pos token.Position, want, got []protocol.CompletionItem) string {
	if len(got) != len(want) {
	goto Failed
	}
	for i, w := range want {
	g := got[i]
	if w.Label != g.Label {
	goto Failed
	}
	if w.Detail != g.Detail {
	goto Failed
	}
	if w.Kind != g.Kind {
	goto Failed
	}
	}
	return ""
	Failed:
	msg := &bytes.Buffer{}
	fmt.Fprintf(msg, "completion failed for %s:%v:%v:\nexpected:\n", filepath.Base(pos.Filename), pos.Line, pos.Column)
	for _, d := range want {
	fmt.Fprintf(msg, " %v\n", d)
	}
	fmt.Fprintf(msg, "got:\n")
	for _, d := range got {
	fmt.Fprintf(msg, " %v\n", d)
	}
	return msg.String()
	}

	func (f formats) test(t testing.T, s server) {
	for filename, gofmted := range f {
	edits, err := s.Formatting(context.Background(), &protocol.DocumentFormattingParams{
	TextDocument: protocol.TextDocumentIdentifier{
	URI: protocol.DocumentURI(source.ToURI(filename)),
	},
	})
	if err != nil {
	if gofmted != "" {
	t.Error(err)
	}
	continue
	}
	f, err := s.view.GetFile(context.Background(), source.ToURI(filename))
	if err != nil {
	t.Error(err)
	}
	original, err := f.Read()
	if err != nil {
	t.Error(err)
	}
	var ops []*diff.Op
	for _, edit := range edits {
	start := int(edit.Range.Start.Line)
	end := int(edit.Range.End.Line)
	if start == end && edit.Range.End.Character > 1 {
	end++
	}
	if edit.NewText == "" { // deletion
	ops = append(ops, &diff.Op{
	Kind: diff.Delete,
	I1: start,
	I2: end,
	})
	} else if edit.Range.Start == edit.Range.End { // insertion
	ops = append(ops, &diff.Op{
	Kind: diff.Insert,
	Content: edit.NewText,
	I1: start,
	I2: end,
	})
	}
	}
	split := strings.SplitAfter(string(original), "\n")
	got := strings.Join(diff.ApplyEdits(split, ops), "")
	if gofmted != got {
	t.Errorf("format failed for %s: expected '%v', got '%v'", filename, gofmted, got)
	}
	}
	}

	func (f formats) collect(pos token.Position) {
	cmd := exec.Command("gofmt", pos.Filename)
	stdout := bytes.NewBuffer(nil)
	cmd.Stdout = stdout
	cmd.Run() // ignore error, sometimes we have intentionally ungofmt-able files
	f[pos.Filename] = stdout.String()
	}

	func (d definitions) test(t testing.T, s server, typ bool) {
	for src, target := range d {
	params := &protocol.TextDocumentPositionParams{
	TextDocument: protocol.TextDocumentIdentifier{
	URI: src.URI,
	},
	Position: src.Range.Start,
	}
	var locs []protocol.Location
	var err error
	if typ {
	locs, err = s.TypeDefinition(context.Background(), params)
	} else {
	locs, err = s.Definition(context.Background(), params)
	}
	if err != nil {
	t.Fatalf("failed for %s: %v", src, err)
	}
	if len(locs) != 1 {
	t.Errorf("got %d locations for definition, expected 1", len(locs))
	}
	if locs[0] != target {
	t.Errorf("for %v got %v want %v", src, locs[0], target)
	}
	}
	}

	func (d definitions) collect(fset *token.FileSet, src, target packagestest.Range) {
	loc := toProtocolLocation(fset, source.Range(src))
	d[loc] = toProtocolLocation(fset, source.Range(target))
	}