fix(assertions): hasResourceProperties is incompatible with `Match.…

…not` and `Match.absent` (aws#16678)

Fixes aws#16626.

This PR modifies `hasResourceProperties()` so that it accounts for the special case where `Properties` does not exist on the template. The following assertions previously behaved incorrectly when `Properties` were not in the template and are now fixed:

```ts
template.fromStack(stack); // some template with no `Properties`.

// assert that `Properties` does not exist in the template. Returns true.
template.hasResourceProperties('Foo::Bar', Match.absent());

// assert that `baz` is not a `Property` of 'Foo::Bar'. Returns true.
template.hasResourceProperties('Foo::Bar', {
   baz: Match.absent(),
};

// assert that `baz` does not have a value of `qux` in the `Properties` object. Returns true.
template.hasResourceProperties('Foo::Bar', Match.not({baz: 'qux'});
```

It also moves `AbsentMatch` into the `private` folder so that it can be exposed internally as a special case for `hasResourceProperties()`.

----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

packages/@aws-cdk/assertions/lib/match.ts

@@ -1,4 +1,5 @@
 import { Matcher, MatchResult } from './matcher';
+import { AbsentMatch } from './private/matchers/absent';
 import { getType } from './private/type';
 
 /**
@@ -329,17 +330,3 @@ class AnyMatch extends Matcher {
     return result;
   }
 }
-
-class AbsentMatch extends Matcher {
-  constructor(public readonly name: string) {
-    super();
-  }
-
-  public test(actual: any): MatchResult {
-    const result = new MatchResult(actual);
-    if (actual !== undefined) {
-      result.push(this, [], `Received ${actual}, but key should be absent`);
-    }
-    return result;
-  }
-}

packages/@aws-cdk/assertions/lib/private/matchers/absent.ts

@@ -0,0 +1,15 @@
+import { Matcher, MatchResult } from '../../matcher';
+
+export class AbsentMatch extends Matcher {
+  constructor(public readonly name: string) {
+    super();
+  }
+
+  public test(actual: any): MatchResult {
+    const result = new MatchResult(actual);
+    if (actual !== undefined) {
+      result.push(this, [], `Received ${actual}, but key should be absent`);
+    }
+    return result;
+  }
+}

packages/@aws-cdk/assertions/lib/private/resources.ts

@@ -1,3 +1,5 @@
+import { Match, Matcher } from '..';
+import { AbsentMatch } from './matchers/absent';
 import { formatFailure, matchSection } from './section';
 import { Resource, Template } from './template';
 
@@ -15,7 +17,6 @@ export function findResources(template: Template, type: string, props: any = {})
 export function hasResource(template: Template, type: string, props: any): string | void {
   const section = template.Resources;
   const result = matchSection(filterType(section, type), props);
-
   if (result.match) {
     return;
   }
@@ -30,13 +31,39 @@ export function hasResource(template: Template, type: string, props: any): strin
   ].join('\n');
 }
 
+export function hasResourceProperties(template: Template, type: string, props: any): string | void {
+  // amended needs to be a deep copy to avoid modifying the template.
+  let amended = JSON.parse(JSON.stringify(template));
+
+  // special case to exclude AbsentMatch because adding an empty Properties object will affect its evaluation.
+  if (!Matcher.isMatcher(props) || !(props instanceof AbsentMatch)) {
+    amended = addEmptyProperties(amended);
+  }
+
+  return hasResource(amended, type, Match.objectLike({
+    Properties: props,
+  }));
+}
+
 export function countResources(template: Template, type: string): number {
   const section = template.Resources;
   const types = filterType(section, type);
 
   return Object.entries(types).length;
 }
 
+function addEmptyProperties(template: Template): Template {
+  let section = template.Resources;
+
+  Object.keys(section).map((key) => {
+    if (!section[key].hasOwnProperty('Properties')) {
+      section[key].Properties = {};
+    }
+  });
+
+  return template;
+}
+
 function filterType(section: { [key: string]: Resource }, type: string): { [key: string]: Resource } {
   return Object.entries(section ?? {})
     .filter(([_, v]) => v.Type === type)

packages/@aws-cdk/assertions/lib/template.ts

@@ -3,7 +3,7 @@ import { Match } from './match';
 import { Matcher } from './matcher';
 import { findMappings, hasMapping } from './private/mappings';
 import { findOutputs, hasOutput } from './private/outputs';
-import { countResources, findResources, hasResource } from './private/resources';
+import { countResources, findResources, hasResource, hasResourceProperties } from './private/resources';
 import { Template as TemplateType } from './private/template';
 
 /**
@@ -74,9 +74,10 @@ export class Template {
    * @param props the 'Properties' section of the resource as should be expected in the template.
    */
   public hasResourceProperties(type: string, props: any): void {
-    this.hasResource(type, Match.objectLike({
-      Properties: Matcher.isMatcher(props) ? props : Match.objectLike(props),
-    }));
+    const matchError = hasResourceProperties(this.template, type, props);
+    if (matchError) {
+      throw new Error(matchError);
+    }
   }
 
   /**

packages/@aws-cdk/assertions/test/template.test.ts

@@ -270,33 +270,56 @@ describe('Template', () => {
   });
 
   describe('hasResourceProperties', () => {
-    test('absent', () => {
+    test('exact match', () => {
+      const stack = new Stack();
+      new CfnResource(stack, 'Foo', {
+        type: 'Foo::Bar',
+        properties: { baz: 'qux' },
+      });
+
+      const inspect = Template.fromStack(stack);
+      inspect.hasResourceProperties('Foo::Bar', { baz: 'qux' });
+
+      expect(() => inspect.hasResourceProperties('Foo::Bar', { baz: 'waldo' }))
+        .toThrow(/Expected waldo but received qux at \/Properties\/baz/);
+
+      expect(() => inspect.hasResourceProperties('Foo::Bar', { baz: 'qux', fred: 'waldo' }))
+        .toThrow(/Missing key at \/Properties\/fred/);
+    });
+
+    test('absent - with properties', () => {
       const stack = new Stack();
       new CfnResource(stack, 'Foo', {
         type: 'Foo::Bar',
         properties: { baz: 'qux' },
       });
 
       const inspect = Template.fromStack(stack);
+
       inspect.hasResourceProperties('Foo::Bar', {
         bar: Match.absent(),
       });
+
       expect(() => inspect.hasResourceProperties('Foo::Bar', {
         baz: Match.absent(),
       })).toThrow(/key should be absent at \/Properties\/baz/);
     });
 
-    test('absent - no properties on template', () => {
+    test('absent - no properties', () => {
       const stack = new Stack();
       new CfnResource(stack, 'Foo', {
         type: 'Foo::Bar',
       });
 
       const inspect = Template.fromStack(stack);
+
+      expect(() => inspect.hasResourceProperties('Foo::Bar', { bar: Match.absent(), baz: 'qux' }))
+        .toThrow(/Missing key at \/Properties\/baz/);
+
       inspect.hasResourceProperties('Foo::Bar', Match.absent());
     });
 
-    test('not', () => {
+    test('not - with properties', () => {
       const stack = new Stack();
       new CfnResource(stack, 'Foo', {
         type: 'Foo::Bar',
@@ -308,6 +331,16 @@ describe('Template', () => {
         baz: 'boo',
       }));
     });
+
+    test('not - no properties', () => {
+      const stack = new Stack();
+      new CfnResource(stack, 'Foo', {
+        type: 'Foo::Bar',
+      });
+
+      const inspect = Template.fromStack(stack);
+      inspect.hasResourceProperties('Foo::Bar', Match.not({ baz: 'qux' }));
+    });
   });
 
   describe('getResources', () => {