internal/lsp: add InlayHint regtests

Add regtests for inlay hints to verify we can turn on
and off different inlay hints.

Change-Id: Id88450c40c048b6c2544d22a0d3eadb57b70a723
Reviewed-on: https://go-review.googlesource.com/c/tools/+/411911
Reviewed-by: Robert Findley <rfindley@google.com>
Reviewed-by: Jamal Carvalho <jamal@golang.org>
gopls-CI: kokoro <noreply+kokoro@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Suzy Mueller <suzmue@golang.org>

gopls/internal/regtest/inlayHints/inlayHints_test.go

@@ -0,0 +1,72 @@
+// Copyright 2022 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 inlayHint
+
+import (
+	"testing"
+
+	"golang.org/x/tools/gopls/internal/hooks"
+	"golang.org/x/tools/internal/lsp/bug"
+	. "golang.org/x/tools/internal/lsp/regtest"
+	"golang.org/x/tools/internal/lsp/source"
+	"golang.org/x/tools/internal/testenv"
+)
+
+func TestMain(m *testing.M) {
+	bug.PanicOnBugs = true
+	Main(m, hooks.Options)
+}
+func TestEnablingInlayHints(t *testing.T) {
+	testenv.NeedsGo1Point(t, 14) // Test fails on 1.13.
+	const workspace = `
+-- go.mod --
+module inlayHint.test
+go 1.12
+-- lib.go --
+package lib
+type Number int
+const (
+	Zero Number = iota
+	One
+	Two
+)
+`
+	tests := []struct {
+		label         string
+		enabled       map[string]bool
+		wantInlayHint bool
+	}{
+		{
+			label:         "default",
+			wantInlayHint: false,
+		},
+		{
+			label:         "enable const",
+			enabled:       map[string]bool{source.ConstantValues: true},
+			wantInlayHint: true,
+		},
+		{
+			label:         "enable parameter names",
+			enabled:       map[string]bool{source.ParameterNames: true},
+			wantInlayHint: false,
+		},
+	}
+	for _, test := range tests {
+		t.Run(test.label, func(t *testing.T) {
+			WithOptions(
+				EditorConfig{
+					Settings: map[string]interface{}{
+						"hints": test.enabled,
+					},
+				},
+			).Run(t, workspace, func(t *testing.T, env *Env) {
+				env.OpenFile("lib.go")
+				lens := env.InlayHints("lib.go")
+				if gotInlayHint := len(lens) > 0; gotInlayHint != test.wantInlayHint {
+					t.Errorf("got inlayHint: %t, want %t", gotInlayHint, test.wantInlayHint)
+				}
+			})
+		})
+	}
+}

internal/lsp/fake/editor.go

@@ -1114,6 +1114,27 @@ func (e *Editor) Symbols(ctx context.Context, sym string) ([]protocol.SymbolInfo
 	return ans, err
 }
 
+// CodeLens executes a codelens request on the server.
+func (e *Editor) InlayHint(ctx context.Context, path string) ([]protocol.InlayHint, error) {
+	if e.Server == nil {
+		return nil, nil
+	}
+	e.mu.Lock()
+	_, ok := e.buffers[path]
+	e.mu.Unlock()
+	if !ok {
+		return nil, fmt.Errorf("buffer %q is not open", path)
+	}
+	params := &protocol.InlayHintParams{
+		TextDocument: e.textDocumentIdentifier(path),
+	}
+	hints, err := e.Server.InlayHint(ctx, params)
+	if err != nil {
+		return nil, err
+	}
+	return hints, nil
+}
+
 // References executes a reference request on the server.
 func (e *Editor) References(ctx context.Context, path string, pos Pos) ([]protocol.Location, error) {
 	if e.Server == nil {

internal/lsp/regtest/wrappers.go

@@ -358,6 +358,17 @@ func (e *Env) ExecuteCommand(params *protocol.ExecuteCommandParams, result inter
 	}
 }
 
+// InlayHints calls textDocument/inlayHints for the given path, calling t.Fatal on
+// any error.
+func (e *Env) InlayHints(path string) []protocol.InlayHint {
+	e.T.Helper()
+	hints, err := e.Editor.InlayHint(e.Ctx, path)
+	if err != nil {
+		e.T.Fatal(err)
+	}
+	return hints
+}
+
 // WorkspaceSymbol calls workspace/symbol
 func (e *Env) WorkspaceSymbol(sym string) []protocol.SymbolInformation {
 	e.T.Helper()