Supports deep equality of Map and Set keys

std/testing/asserts.ts

@@ -69,8 +69,8 @@ function buildMessage(diffResult: ReadonlyArray<DiffResult<string>>): string[] {
 
 function isKeyedCollection(
   x: unknown
-): x is Map<unknown, unknown> | Set<unknown> {
-  return x instanceof Map || x instanceof Set;
+): x is Set<unknown> {
+  return [Symbol.iterator, 'size'].every(k => k in (x as Set<unknown>));
 }
 
 export function equal(c: unknown, d: unknown): boolean {
@@ -101,13 +101,19 @@ export function equal(c: unknown, d: unknown): boolean {
           return false;
         }
 
-        for (const [key, value] of a.entries()) {
-          if (!b.has(key) || !compare(value, "get" in b ? b.get(key) : key)) {
-            return false;
+        let matchedEntries = 0;
+
+        for (const [aKey, aValue] of a.entries()) {
+          for (const [bKey, bValue] of b.entries()) {
+            /* Given that keys can be references, we need
+             * to ensure that they are also deeply equal */
+            if (compare(aKey, bKey) && compare(aValue, bValue)) {
+              matchedEntries++;
+            }
           }
         }
 
-        return true;
+        return matchedEntries === a.size;
       }
       const merged = { ...a, ...b };
       for (const key in merged) {

std/testing/asserts_test.ts

@@ -44,6 +44,7 @@ test(function testingEqual(): void {
   assert(equal(new Set([1]), new Set([1])));
   assert(!equal(new Set([1]), new Set([2])));
   assert(equal(new Set([1, 2, 3]), new Set([3, 2, 1])));
+  assert(equal(new Set([1, new Set([2, 3])]), new Set([new Set([3, 2]), 1])));
   assert(!equal(new Set([1, 2]), new Set([3, 2, 1])));
   assert(!equal(new Set([1, 2, 3]), new Set([4, 5, 6])));
   assert(equal(new Set("denosaurus"), new Set("denosaurussss")));
@@ -84,6 +85,27 @@ test(function testingEqual(): void {
     )
   );
 
+  assert(
+    equal(
+      new Map([[{x: 1}, true]]),
+      new Map([[{x: 1}, true]])
+    )
+  );
+
+  assert(
+    !equal(
+      new Map([[{x: 1}, true]]),
+      new Map([[{x: 1}, false]])
+    )
+  );
+
+  assert(
+    !equal(
+      new Map([[{x: 1}, true]]),
+      new Map([[{x: 2}, false]])
+    )
+  );
+
   assert(equal([1, 2, 3], [1, 2, 3]));
   assert(equal([1, [2, 3]], [1, [2, 3]]));
   assert(!equal([1, 2, 3, 4], [1, 2, 3]));