--- /dev/null
+// Copyright 2019 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 cmdtest
+
+import (
+ "fmt"
+ "sort"
+ "testing"
+
+ "golang.org/x/tools/internal/span"
+)
+
+func (r *runner) Implementation(t *testing.T, spn span.Span, imps []span.Span) {
+ var itemStrings []string
+ for _, i := range imps {
+ itemStrings = append(itemStrings, fmt.Sprint(i))
+ }
+ sort.Strings(itemStrings)
+ var expect string
+ for _, i := range itemStrings {
+ expect += i + "\n"
+ }
+ expect = r.Normalize(expect)
+
+ uri := spn.URI()
+ filename := uri.Filename()
+ target := filename + fmt.Sprintf(":%v:%v", spn.Start().Line(), spn.Start().Column())
+
+ got, stderr := r.NormalizeGoplsCmd(t, "implementation", target)
+ if stderr != "" {
+ t.Errorf("implementation failed for %s: %s", target, stderr)
+ } else if expect != got {
+ t.Errorf("implementation failed for %s expected:\n%s\ngot:\n%s", target, expect, got)
+ }
+}