Add ability to stub getEvents with specific filter args (#32)

.changeset/wet-eyes-arrive.md

@@ -0,0 +1,5 @@
+---
+"@delvtech/evm-client": patch
+---
+
+Add ability to stub events for dynamic filter args

packages/evm-client/src/contract/factories/CachedReadContract.test.ts

@@ -45,7 +45,7 @@ describe('createCachedReadContract', () => {
         transactionHash: '0x123abc',
       },
     ];
-    contract.stubEvents('Transfer', stubbedEvents);
+    contract.stubEvents('Transfer', undefined, stubbedEvents);
 
     const events = await cachedContract.getEvents('Transfer');
     expect(events).toBe(stubbedEvents);

packages/evm-client/src/contract/stubs/ReadContractStub.test.ts

@@ -75,9 +75,11 @@ describe('ReadContractStub', () => {
   it('stubs the getEvents function', async () => {
     const contract = new ReadContractStub(ERC20ABI);
 
+    // throws an error if you forget to stub the event your requesting
     expect(contract.getEvents('Transfer')).rejects.toThrowError();
 
-    const stubbedEvents: Event<typeof ERC20ABI, 'Transfer'>[] = [
+    // Stub out the events when calling `getEvents` without any filter args
+    const stubbedAllEvents: Event<typeof ERC20ABI, 'Transfer'>[] = [
       {
         eventName: 'Transfer',
         args: {
@@ -89,13 +91,56 @@ describe('ReadContractStub', () => {
         data: '0x123abc',
         transactionHash: '0x123abc',
       },
+      {
+        eventName: 'Transfer',
+        args: {
+          from: ALICE,
+          to: BOB,
+          value: 100n,
+        },
+        blockNumber: 1n,
+        data: '0x123abc',
+        transactionHash: '0x123abc',
+      },
     ];
-    contract.stubEvents('Transfer', stubbedEvents);
+    contract.stubEvents('Transfer', undefined, stubbedAllEvents);
 
+    // Stub out the events when calling `getEvents` *with* filter args
+    const stubbedFilteredEvents: Event<typeof ERC20ABI, 'Transfer'>[] = [
+      {
+        eventName: 'Transfer',
+        args: {
+          to: ALICE,
+          from: BOB,
+          value: 100n,
+        },
+        blockNumber: 1n,
+        data: '0x123abc',
+        transactionHash: '0x123abc',
+      },
+    ];
+    contract.stubEvents(
+      'Transfer',
+      { filter: { from: BOB } },
+      stubbedFilteredEvents,
+    );
+
+    // getting events without any filter args should return the stub that was
+    // specified without any filter args
     const events = await contract.getEvents('Transfer');
-    expect(events).toBe(stubbedEvents);
-
+    expect(events).toBe(stubbedAllEvents);
     const stub = contract.getEventsStub('Transfer');
     expect(stub?.callCount).toBe(1);
+
+    // getting events with filter args should return the stub that was specified
+    // *with* filter args
+    const filteredEvents = await contract.getEvents('Transfer', {
+      filter: { from: BOB },
+    });
+    expect(filteredEvents).toBe(stubbedFilteredEvents);
+    const filteredStub = contract.getEventsStub('Transfer', {
+      filter: { from: BOB },
+    });
+    expect(filteredStub?.callCount).toBe(1);
   });
 });

packages/evm-client/src/contract/stubs/ReadContractStub.ts

@@ -98,7 +98,7 @@ export class ReadContractStub<TAbi extends Abi = Abi>
   async getEvents<TEventName extends EventName<TAbi>>(
     ...[eventName, options]: ContractGetEventsArgs<TAbi, TEventName>
   ): Promise<Event<TAbi, TEventName>[]> {
-    const stub = this.getEventsStub(eventName);
+    const stub = this.getEventsStub(eventName, options);
     if (!stub) {
       throw new Error(
         `Called getEvents for ${eventName} on a stubbed contract without a return value. The function must be stubbed first:\n\tcontract.stubEvents("${eventName}", value)`,
@@ -162,18 +162,17 @@ export class ReadContractStub<TAbi extends Abi = Abi>
    * Stubs the return value for a given event name when `getEvents` is called
    * with that event name. This method overrides any previously stubbed values
    * for the same event.
-   *
-   * *Note: The stub doesn't account for dynamic values based on provided
-   * arguments/options.*
    */
   stubEvents<TEventName extends EventName<TAbi>>(
     eventName: TEventName,
+    args: ContractGetEventsOptions<TAbi, TEventName> | undefined,
     value: Event<TAbi, TEventName>[],
   ): void {
-    if (this.eventsStubMap.has(eventName)) {
-      this.getEventsStub(eventName)!.resolves(value);
+    const stubKey = stringify({ eventName, args });
+    if (this.eventsStubMap.has(stubKey)) {
+      this.getEventsStub(eventName, args)!.resolves(value as any);
     } else {
-      this.eventsStubMap.set(eventName, stub().resolves(value) as any);
+      this.eventsStubMap.set(stubKey, stub().resolves(value) as any);
     }
   }
 
@@ -209,8 +208,10 @@ export class ReadContractStub<TAbi extends Abi = Abi>
    */
   getEventsStub<TEventName extends EventName<TAbi>>(
     eventName: TEventName,
+    args?: ContractGetEventsOptions<TAbi, TEventName> | undefined,
   ): EventsStub<TAbi, TEventName> | undefined {
-    return this.eventsStubMap.get(eventName) as
+    const stubKey = stringify({ eventName, args });
+    return this.eventsStubMap.get(stubKey) as
       | EventsStub<TAbi, TEventName>
       | undefined;
   }
@@ -270,3 +271,12 @@ type SimulateWriteStub<
   ],
   Promise<FunctionReturn<TAbi, TFunctionName>>
 >;
+
+function stringify(obj: Record<any, any>) {
+  // simple non-recursive stringify replacer for bigints
+  function replacer(_: any, v: any) {
+    return typeof v === 'bigint' ? v.toString() : v;
+  }
+
+  return JSON.stringify(obj, replacer);
+}