Missing things

build-system/test-configs/dep-check-config.js

@@ -506,9 +506,9 @@ exports.rules = [
     filesMatching: '**/*.js',
     mustNotDependOn: 'src/core/assert/base.js',
     allowlist: [
-      'src/core/assert/dev.js',
-      'src/core/assert/user.js',
-      'src/log.js',
+      'src/core/assert/dev.js->src/core/assert/base.js',
+      'src/core/assert/user.js->src/core/assert/base.js',
+      'src/log.js->src/core/assert/base.js',
     ],
   },
 

src/core/assert/assert.extern.js

@@ -0,0 +1,25 @@
+/**
+ * Copyright 2021 The AMP HTML Authors. 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.
+ */
+
+/**
+ * @fileoverview Type externs for assertions.
+ * @externs
+ */
+
+/**
+ * @typedef {function(?, string=, ...*):?|function(?, !Array<*>)}
+ */
+let AssertionFunction;