Add catalog unittests

mojo/services/catalog/BUILD.gn

Index: mojo/services/catalog/BUILD.gn
diff --git a/mojo/services/catalog/BUILD.gn b/mojo/services/catalog/BUILD.gn
index e1abca92f2b7f0aeed81f7386b5c767d4017d1e0..9dd285a8c8d0ac2276c89265735408e6293ea953 100644
--- a/mojo/services/catalog/BUILD.gn
+++ b/mojo/services/catalog/BUILD.gn
@@ -4,8 +4,10 @@
 
 import("//mojo/public/mojo_application.gni")
 import("//mojo/public/mojo_application_manifest.gni")
+import("//testing/test.gni")
 
 group("catalog") {
+  testonly = true
   deps = [
     ":lib",
   ]
@@ -13,10 +15,16 @@ group("catalog") {
 
 source_set("lib") {
   sources = [
+    "builder.cc",
+    "builder.h",
     "catalog.cc",
     "catalog.h",
+    "entry.cc",
+    "entry.h",
     "loader.cc",
     "loader.h",
+    "store.cc",
+    "store.h",
   ]
 
   deps = [
@@ -34,3 +42,16 @@ mojo_application_manifest("manifest") {
   application_name = "catalog"
   source = "manifest.json"
 }
+
+source_set("unittests") {
+  testonly = true
+  sources = [
+    "builder_unittest.cc",
+  ]
+  deps = [
+    ":lib",
+    "//base",
+    "//mojo/shell/public/cpp",
+    "//testing/gtest",
+  ]
+}