Move first/last unique elements utility functions to android package

Move firstUniqueElements to android.FirstUniqueStrings,
lastUniqueElements to android.LastUniqueStrings, and lastUniquePaths
to android.LastUniquePaths.

Test: m checkbuild
Change-Id: Ieac840405126c7f8f98afb4a4ef35c01a18fe7fb

android/util_test.go

@@ -0,0 +1,120 @@
+// Copyright 2017 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package android
+
+import (
+	"reflect"
+	"testing"
+)
+
+var firstUniqueStringsTestCases = []struct {
+	in  []string
+	out []string
+}{
+	{
+		in:  []string{"a"},
+		out: []string{"a"},
+	},
+	{
+		in:  []string{"a", "b"},
+		out: []string{"a", "b"},
+	},
+	{
+		in:  []string{"a", "a"},
+		out: []string{"a"},
+	},
+	{
+		in:  []string{"a", "b", "a"},
+		out: []string{"a", "b"},
+	},
+	{
+		in:  []string{"b", "a", "a"},
+		out: []string{"b", "a"},
+	},
+	{
+		in:  []string{"a", "a", "b"},
+		out: []string{"a", "b"},
+	},
+	{
+		in:  []string{"a", "b", "a", "b"},
+		out: []string{"a", "b"},
+	},
+	{
+		in:  []string{"liblog", "libdl", "libc++", "libdl", "libc", "libm"},
+		out: []string{"liblog", "libdl", "libc++", "libc", "libm"},
+	},
+}
+
+func TestFirstUniqueStrings(t *testing.T) {
+	for _, testCase := range firstUniqueStringsTestCases {
+		out := FirstUniqueStrings(testCase.in)
+		if !reflect.DeepEqual(out, testCase.out) {
+			t.Errorf("incorrect output:")
+			t.Errorf("     input: %#v", testCase.in)
+			t.Errorf("  expected: %#v", testCase.out)
+			t.Errorf("       got: %#v", out)
+		}
+	}
+}
+
+var lastUniqueStringsTestCases = []struct {
+	in  []string
+	out []string
+}{
+	{
+		in:  []string{"a"},
+		out: []string{"a"},
+	},
+	{
+		in:  []string{"a", "b"},
+		out: []string{"a", "b"},
+	},
+	{
+		in:  []string{"a", "a"},
+		out: []string{"a"},
+	},
+	{
+		in:  []string{"a", "b", "a"},
+		out: []string{"b", "a"},
+	},
+	{
+		in:  []string{"b", "a", "a"},
+		out: []string{"b", "a"},
+	},
+	{
+		in:  []string{"a", "a", "b"},
+		out: []string{"a", "b"},
+	},
+	{
+		in:  []string{"a", "b", "a", "b"},
+		out: []string{"a", "b"},
+	},
+	{
+		in:  []string{"liblog", "libdl", "libc++", "libdl", "libc", "libm"},
+		out: []string{"liblog", "libc++", "libdl", "libc", "libm"},
+	},
+}
+
+func TestLastUniqueStrings(t *testing.T) {
+	for _, testCase := range lastUniqueStringsTestCases {
+		out := LastUniqueStrings(testCase.in)
+		if !reflect.DeepEqual(out, testCase.out) {
+			t.Errorf("incorrect output:")
+			t.Errorf("     input: %#v", testCase.in)
+			t.Errorf("  expected: %#v", testCase.out)
+			t.Errorf("       got: %#v", out)
+		}
+	}
+}