feat: Improve error message for UnexpectedCalls

src/errors.ts

@@ -66,9 +66,32 @@ export class UnmetExpectations extends Error {
   }
 }
 
+/**
+ * Merge property accesses and method calls for the same property
+ * into a single call.
+ *
+ * @example
+ * mergeCalls({ foo: [{ arguments: undefined }, { arguments: [1, 2, 3] }] }
+ * // returns { foo: [{ arguments: [1, 2, 3] } }
+ */
+const mergeCalls = (callMap: CallMap): CallMap => {
+  return new Map(
+    Array.from(callMap.entries()).map(([property, calls]) => {
+      const hasMethodCalls = calls.some((call) => call.arguments);
+      const hasPropertyAccesses = calls.some((call) => !call.arguments);
+
+      if (hasMethodCalls && hasPropertyAccesses) {
+        return [property, calls.filter((call) => call.arguments)];
+      }
+
+      return [property, calls];
+    })
+  );
+};
+
 export class UnexpectedCalls extends Error {
   constructor(unexpectedCalls: CallMap, expectations: Expectation[]) {
-    const printedCalls = Array.from(unexpectedCalls.entries())
+    const printedCalls = Array.from(mergeCalls(unexpectedCalls).entries())
       .map(([property, calls]) =>
         calls
           .map((call) =>

tests/errors.spec.ts

@@ -136,7 +136,15 @@ foobar`
 
       const error = new UnexpectedCalls(
         new Map([
-          ['foo', [{ arguments: [1, 2, 3] }, { arguments: [4, 5, 6] }]],
+          [
+            'foo',
+            [
+              { arguments: undefined },
+              { arguments: [1, 2, 3] },
+              { arguments: undefined },
+              { arguments: [4, 5, 6] },
+            ],
+          ],
           ['bar', [{ arguments: undefined }]],
         ]) as CallMap,
         [e1, e2]