Separate cc_library_headers to its own file and add tests

Preparation for adding cc_library_headers to sdk.

Bug: 148933848
Test: m nothing
Change-Id: Icbc86b21f44dc79393b82be339cf3b133cbf9d8c
diff --git a/cc/library_headers_test.go b/cc/library_headers_test.go
new file mode 100644
index 0000000..42d3735
--- /dev/null
+++ b/cc/library_headers_test.go
@@ -0,0 +1,41 @@
+// Copyright 2020 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 cc
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestLibraryHeaders(t *testing.T) {
+	ctx := testCc(t, `
+	cc_library_headers {
+		name: "headers",
+		export_include_dirs: ["my_include"],
+	}
+	cc_library_static {
+		name: "lib",
+		srcs: ["foo.c"],
+		header_libs: ["headers"],
+	}
+	`)
+
+	// test if header search paths are correctly added
+	cc := ctx.ModuleForTests("lib", "android_arm64_armv8-a_static").Rule("cc")
+	cflags := cc.Args["cFlags"]
+	if !strings.Contains(cflags, " -Imy_include ") {
+		t.Errorf("cflags for libsystem must contain -Imy_include, but was %#v.", cflags)
+	}
+}