1 files changed, 96 insertions, 0 deletions
diff --git a/gopls/internal/lsp/cache/standalone_go116_test.go b/gopls/internal/lsp/cache/standalone_go116_test.go
new file mode 100644
index 000000000..9adf01e6c
--- /dev/null
+++ b/gopls/internal/lsp/cache/standalone_go116_test.go
@@ -0,0 +1,96 @@
+// 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.
+
+//go:build go1.16
+// +build go1.16
+
+package cache
+
+import (
+	"testing"
+)
+
+func TestIsStandaloneFile(t *testing.T) {
+	tests := []struct {
+		desc           string
+		contents       string
+		standaloneTags []string
+		want           bool
+	}{
+		{
+			"new syntax",
+			"//go:build ignore\n\npackage main\n",
+			[]string{"ignore"},
+			true,
+		},
+		{
+			"legacy syntax",
+			"// +build ignore\n\npackage main\n",
+			[]string{"ignore"},
+			true,
+		},
+		{
+			"multiple tags",
+			"//go:build ignore\n\npackage main\n",
+			[]string{"exclude", "ignore"},
+			true,
+		},
+		{
+			"invalid tag",
+			"// +build ignore\n\npackage main\n",
+			[]string{"script"},
+			false,
+		},
+		{
+			"non-main package",
+			"//go:build ignore\n\npackage p\n",
+			[]string{"ignore"},
+			false,
+		},
+		{
+			"alternate tag",
+			"// +build script\n\npackage main\n",
+			[]string{"script"},
+			true,
+		},
+		{
+			"both syntax",
+			"//go:build ignore\n// +build ignore\n\npackage main\n",
+			[]string{"ignore"},
+			true,
+		},
+		{
+			"after comments",
+			"// A non-directive comment\n//go:build ignore\n\npackage main\n",
+			[]string{"ignore"},
+			true,
+		},
+		{
+			"after package decl",
+			"package main //go:build ignore\n",
+			[]string{"ignore"},
+			false,
+		},
+		{
+			"on line after package decl",
+			"package main\n\n//go:build ignore\n",
+			[]string{"ignore"},
+			false,
+		},
+		{
+			"combined with other expressions",
+			"\n\n//go:build ignore || darwin\n\npackage main\n",
+			[]string{"ignore"},
+			false,
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.desc, func(t *testing.T) {
+			if got := isStandaloneFile([]byte(test.contents), test.standaloneTags); got != test.want {
+				t.Errorf("isStandaloneFile(%q, %v) = %t, want %t", test.contents, test.standaloneTags, got, test.want)
+			}
+		})
+	}
+}