1 files changed, 100 insertions, 0 deletions
diff --git a/src/cmd/go/internal/str/str_test.go b/src/cmd/go/internal/str/str_test.go
new file mode 100644
index 0000000..158fe65
--- /dev/null
+++ b/src/cmd/go/internal/str/str_test.go
@@ -0,0 +1,100 @@
+// Copyright 2020 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 str
+
+import (
+	"os"
+	"runtime"
+	"testing"
+)
+
+var foldDupTests = []struct {
+	list   []string
+	f1, f2 string
+}{
+	{StringList("math/rand", "math/big"), "", ""},
+	{StringList("math", "strings"), "", ""},
+	{StringList("strings"), "", ""},
+	{StringList("strings", "strings"), "strings", "strings"},
+	{StringList("Rand", "rand", "math", "math/rand", "math/Rand"), "Rand", "rand"},
+}
+
+func TestFoldDup(t *testing.T) {
+	for _, tt := range foldDupTests {
+		f1, f2 := FoldDup(tt.list)
+		if f1 != tt.f1 || f2 != tt.f2 {
+			t.Errorf("foldDup(%q) = %q, %q, want %q, %q", tt.list, f1, f2, tt.f1, tt.f2)
+		}
+	}
+}
+
+type trimFilePathPrefixTest struct {
+	s, prefix, want string
+}
+
+func TestTrimFilePathPrefixSlash(t *testing.T) {
+	if os.PathSeparator != '/' {
+		t.Skipf("test requires slash-separated file paths")
+	}
+	tests := []trimFilePathPrefixTest{
+		{"/foo", "", "foo"},
+		{"/foo", "/", "foo"},
+		{"/foo", "/foo", ""},
+		{"/foo/bar", "/foo", "bar"},
+		{"/foo/bar", "/foo/", "bar"},
+		// if prefix is not s's prefix, return s
+		{"/foo", "/bar", "/foo"},
+		{"/foo", "/foo/bar", "/foo"},
+	}
+
+	for _, tt := range tests {
+		if got := TrimFilePathPrefix(tt.s, tt.prefix); got != tt.want {
+			t.Errorf("TrimFilePathPrefix(%q, %q) = %q, want %q", tt.s, tt.prefix, got, tt.want)
+		}
+	}
+}
+
+func TestTrimFilePathPrefixWindows(t *testing.T) {
+	if runtime.GOOS != "windows" {
+		t.Skipf("test requires Windows file paths")
+	}
+	tests := []trimFilePathPrefixTest{
+		{`C:\foo`, `C:`, `foo`},
+		{`C:\foo`, `C:\`, `foo`},
+		{`C:\foo`, `C:\foo`, ``},
+		{`C:\foo\bar`, `C:\foo`, `bar`},
+		{`C:\foo\bar`, `C:\foo\`, `bar`},
+		// if prefix is not s's prefix, return s
+		{`C:\foo`, `C:\bar`, `C:\foo`},
+		{`C:\foo`, `C:\foo\bar`, `C:\foo`},
+		// if volumes are different, return s
+		{`C:\foo`, ``, `C:\foo`},
+		{`C:\foo`, `\foo`, `C:\foo`},
+		{`C:\foo`, `D:\foo`, `C:\foo`},
+
+		//UNC path
+		{`\\host\share\foo`, `\\host\share`, `foo`},
+		{`\\host\share\foo`, `\\host\share\`, `foo`},
+		{`\\host\share\foo`, `\\host\share\foo`, ``},
+		{`\\host\share\foo\bar`, `\\host\share\foo`, `bar`},
+		{`\\host\share\foo\bar`, `\\host\share\foo\`, `bar`},
+		// if prefix is not s's prefix, return s
+		{`\\host\share\foo`, `\\host\share\bar`, `\\host\share\foo`},
+		{`\\host\share\foo`, `\\host\share\foo\bar`, `\\host\share\foo`},
+		// if either host or share name is different, return s
+		{`\\host\share\foo`, ``, `\\host\share\foo`},
+		{`\\host\share\foo`, `\foo`, `\\host\share\foo`},
+		{`\\host\share\foo`, `\\host\other\`, `\\host\share\foo`},
+		{`\\host\share\foo`, `\\other\share\`, `\\host\share\foo`},
+		{`\\host\share\foo`, `\\host\`, `\\host\share\foo`},
+		{`\\host\share\foo`, `\share\`, `\\host\share\foo`},
+	}
+
+	for _, tt := range tests {
+		if got := TrimFilePathPrefix(tt.s, tt.prefix); got != tt.want {
+			t.Errorf("TrimFilePathPrefix(%q, %q) = %q, want %q", tt.s, tt.prefix, got, tt.want)
+		}
+	}
+}