Better formatting of metrics

Author: Dave Bartolomeo

extensions/ql-vscode/src/log-insights/join-order.ts

@@ -192,7 +192,7 @@ class JoinOrderScanner implements EvaluationLogScanner {
   private reportProblemIfNecessary(event: SummaryEvent, iteration: number, metric: number): void {
     if (metric >= this.warningThreshold) {
       this.problemReporter.reportProblem(event.predicateName, event.raHash, iteration,
-        `Relation '${event.predicateName}' has an inefficient join order. Its join order metric is ${metric}, which is larger than the threshold of ${this.warningThreshold}.`);
+        `Relation '${event.predicateName}' has an inefficient join order. Its join order metric is ${metric.toFixed(2)}, which is larger than the threshold of ${this.warningThreshold.toFixed(2)}.`);
     }
   }
 

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

@@ -36,6 +36,6 @@ describe('log scanners', function() {
     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.');
+    expect(problemReporter.problems[0].message).to.equal('Relation \'#select#ff\' has an inefficient join order. Its join order metric is 4961.83, which is larger than the threshold of 50.00.');
   });
 });