Test for log scanning

extensions/ql-vscode/test/pure-tests/log-scanner.test.ts

@@ -0,0 +1,41 @@
+import { expect } from 'chai';
+import 'mocha';
+import { EvaluationLogProblemReporter, EvaluationLogScannerSet } from '../../src/log-insights/log-scanner';
+import { JoinOrderScannerProvider } from '../../src/log-insights/join-order';
+import * as path from 'path';
+
+interface TestProblem {
+  predicateName: string;
+  raHash: string;
+  iteration: number;
+  message: string;
+}
+
+class TestProblemReporter implements EvaluationLogProblemReporter {
+  public readonly problems: TestProblem[] = [];
+
+  public reportProblem(predicateName: string, raHash: string, iteration: number, message: string): void {
+    this.problems.push({
+      predicateName,
+      raHash,
+      iteration,
+      message
+    });
+  }
+}
+
+describe('log scanners', function() {
+  it('should detect bad join orders', async function() {
+    const scanners = new EvaluationLogScannerSet();
+    scanners.registerLogScannerProvider(new JoinOrderScannerProvider());
+    const summaryPath = path.join(__dirname, 'evaluator-log-summaries/bad-join-order.jsonl');
+    const problemReporter = new TestProblemReporter();
+    await scanners.scanLog(summaryPath, problemReporter);
+
+    expect(problemReporter.problems.length).to.equal(1);
+    expect(problemReporter.problems[0].predicateName).to.equal('#select#ff');
+    expect(problemReporter.problems[0].raHash).to.equal('1bb43c97jpmuh8r2v0f9hktim63');
+    expect(problemReporter.problems[0].iteration).to.equal(0);
+    expect(problemReporter.problems[0].message).to.equal('Relation \'#select#ff\' has an inefficient join order. Its join order metric is 4961.834409325194, which is larger than the threshold of 50.');
+  });
+});