output: buffered content more tests

src/vs/workbench/parts/output/browser/outputServices.ts

@@ -50,11 +50,11 @@ export class BufferedContent {
 	}
 
 	private trim(): void {
-		if (this.length < MAX_OUTPUT_LENGTH * 1.5) {
+		if (this.length < MAX_OUTPUT_LENGTH * 1.2) {
 			return;
 		}
 
-		while (this.length > MAX_OUTPUT_LENGTH && this.data.length) {
+		while (this.length > MAX_OUTPUT_LENGTH) {
 			this.dataIds.shift();
 			const removed = this.data.shift();
 			this.length -= removed.length;
@@ -68,8 +68,8 @@ export class BufferedContent {
 		}
 
 		const id = this.idPool;
-		if (idx > 0) {
-			const value = strings.removeAnsiEscapeCodes(this.data.slice(idx).join(''));
+		if (idx >= 0) {
+			const value = strings.removeAnsiEscapeCodes(this.data.slice(idx + 1).join(''));
 			return { value, id, append: true };
 		} else {
 			const value = strings.removeAnsiEscapeCodes(this.data.join(''));

src/vs/workbench/parts/output/test/bufferedContent.test.ts

@@ -20,16 +20,40 @@ suite('Workbench - Output Buffered Content', () => {
 		assert.equal(bufferedContent.getDelta(delta).value, '');
 	});
 
-	test('Buffered Content - Lots of output', () => {
+	test('Buffered Content - Appending Output', () => {
+		const bufferedContent = new BufferedContent();
+		bufferedContent.append('first');
+		const firstDelta = bufferedContent.getDelta();
+		bufferedContent.append('second');
+		bufferedContent.append('third');
+		const secondDelta = bufferedContent.getDelta(firstDelta);
+		assert.equal(secondDelta.append, true);
+		assert.equal(secondDelta.value, 'secondthird');
+		bufferedContent.append('fourth');
+		bufferedContent.append('fifth');
+		assert.equal(bufferedContent.getDelta(firstDelta).value, 'secondthirdfourthfifth');
+		assert.equal(bufferedContent.getDelta(secondDelta).value, 'fourthfifth');
+	});
+
+	test('Buffered Content - Lots of Output', () => {
 		const bufferedContent = new BufferedContent();
 		bufferedContent.append('first line');
 		const firstDelta = bufferedContent.getDelta();
-		for (var i = 0; i < 100000; i++) {
+		let longString = '';
+		for (var i = 0; i < 50000; i++) {
 			bufferedContent.append(i.toString());
+			longString += i.toString();
 		}
 		const secondDelta = bufferedContent.getDelta(firstDelta);
-		assert.equal(!!secondDelta.append, false);
-		assert.equal(secondDelta.value.substr(secondDelta.value.length - 5), '99999');
+		assert.equal(secondDelta.append, true);
+		assert.equal(secondDelta.value.substr(secondDelta.value.length - 5), '49999');
+		longString = longString + longString + longString + longString;
+		bufferedContent.append(longString);
+		bufferedContent.append(longString);
+		const thirdDelta = bufferedContent.getDelta(firstDelta);
+		assert.equal(!!thirdDelta.append, false);
+		assert.equal(thirdDelta.value.substr(thirdDelta.value.length - 5), '49999');
+
 		bufferedContent.clear();
 		assert.equal(bufferedContent.getDelta().value, '');
 	});