1 files changed, 62 insertions, 0 deletions
diff --git a/gopls/internal/lsp/snippet/snippet_builder_test.go b/gopls/internal/lsp/snippet/snippet_builder_test.go
new file mode 100644
index 000000000..bc814b16d
--- /dev/null
+++ b/gopls/internal/lsp/snippet/snippet_builder_test.go
@@ -0,0 +1,62 @@
+// 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 snippet
+
+import (
+	"testing"
+)
+
+func TestSnippetBuilder(t *testing.T) {
+	expect := func(expected string, fn func(*Builder)) {
+		t.Helper()
+
+		var b Builder
+		fn(&b)
+		if got := b.String(); got != expected {
+			t.Errorf("got %q, expected %q", got, expected)
+		}
+	}
+
+	expect("", func(b *Builder) {})
+
+	expect(`hi { \} \$ | " , / \\`, func(b *Builder) {
+		b.WriteText(`hi { } $ | " , / \`)
+	})
+
+	expect("${1:}", func(b *Builder) {
+		b.WritePlaceholder(nil)
+	})
+
+	expect("hi ${1:there}", func(b *Builder) {
+		b.WriteText("hi ")
+		b.WritePlaceholder(func(b *Builder) {
+			b.WriteText("there")
+		})
+	})
+
+	expect(`${1:id=${2:{your id\}}}`, func(b *Builder) {
+		b.WritePlaceholder(func(b *Builder) {
+			b.WriteText("id=")
+			b.WritePlaceholder(func(b *Builder) {
+				b.WriteText("{your id}")
+			})
+		})
+	})
+
+	expect(`${1|one,{ \} \$ \| " \, / \\,three|}`, func(b *Builder) {
+		b.WriteChoice([]string{"one", `{ } $ | " , / \`, "three"})
+	})
+
+	expect("$0 hello", func(b *Builder) {
+		b.WriteFinalTabstop()
+		b.WriteText(" hello")
+	})
+
+	expect(`prepended \$5 ${1:} hello`, func(b *Builder) {
+		b.WritePlaceholder(nil)
+		b.WriteText(" hello")
+		b.PrependText("prepended $5 ")
+	})
+}