@0x/contracts-test-utils: Add filterLogs() and

`filterLogsToArguments()` helpers.

contracts/test-utils/src/log_utils.ts

@@ -0,0 +1,17 @@
+import { LogEntry, LogWithDecodedArgs } from 'ethereum-types';
+
+// tslint:disable no-unnecessary-type-assertion
+
+/**
+ * Filter logs by event name/type.
+ */
+export function filterLogs<TEventArgs>(logs: LogEntry[], event: string): Array<LogWithDecodedArgs<TEventArgs>> {
+    return (logs as Array<LogWithDecodedArgs<any>>).filter(log => log.event === event);
+}
+
+/**
+ * Filter logs by event name/type and convert to arguments.
+ */
+export function filterLogsToArguments<TEventArgs>(logs: LogEntry[], event: string): TEventArgs[] {
+    return filterLogs<TEventArgs>(logs, event).map(log => log.args);
+}