test: verify outputs of examples/out_dir test (#633)

examples/out_dir/BUILD.bazel

@@ -1,4 +1,5 @@
 load("@aspect_rules_ts//ts:defs.bzl", "ts_project")
+load("@bazel_skylib//rules:build_test.bzl", "build_test")
 
 ts_project(
     name = "out_dir-tsconfig",
@@ -30,3 +31,26 @@ ts_project(
     out_dir = "declaration_dir",
     tsconfig = {},
 )
+
+build_test(
+    name = "test",
+    targets = [
+        # outputs specified by the tsconfig attr
+        ":out_dir-tsconfig",
+        "tsconfig/main.js",
+        "tsconfig/main.d.ts",
+        "tsconfig/main.d.ts.map",
+
+        # outputs specified by the ts_project attrs
+        ":out_dir-params",
+        "param/main.js",
+        "param/main.d.ts",
+        "param/main.d.ts.map",
+
+        # outptus specified with out_dir *and* declaration_dir
+        ":out_dir-declaration_dir",
+        "declaration_dir/main.js",
+        "decl_map/main.d.ts",
+        "decl_map/main.d.ts.map",
+    ],
+)