A test with the mock arch

Change-Id: I9af804df9cf1019f0b9c5535d7d79aca28229f88
diff --git a/BUILD.gn b/BUILD.gn
index cef1259..622f91e 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -1,6 +1,23 @@
 import("//build/image/image.gni")
 
-group("arch_images") {
+group("tests") {
+  testonly = true
+
+  deps = [
+    ":unit_tests",
+    ":vm_tests",
+  ]
+}
+
+group("unit_tests") {
+  testonly = true
+
+  deps = [
+    "//src:unit_tests($mock_toolchain)",
+  ]
+}
+
+group("vm_tests") {
   testonly = true
 
   deps = [