diff --git a/test/api/Terminal.api.ts b/test/api/Terminal.api.ts
index 0e50e7fc..43f1e97d 100644
--- a/test/api/Terminal.api.ts
+++ b/test/api/Terminal.api.ts
@@ -731,35 +731,61 @@ describe('API Integration Tests', function(): void {
     await pollFor(page, `window.term._core._renderService.dimensions.actualCellWidth > 0`, true);
   });
 
-  describe.only('registerDecoration', () => {
-    it('should register decorations and render them when terminal open is called', async () => {
-      await page.evaluate(`window.term = new Terminal({})`);
-      await page.evaluate(`window.term.open(document.querySelector('#terminal-container'))`);
-      await page.waitForSelector('.xterm-text-layer');
-      await page.evaluate(`window.marker1 = window.term.addMarker(1)`);
-      await page.evaluate(`window.marker2 = window.term.addMarker(2)`);
-      await page.evaluate(`window.term.registerDecoration({ marker: window.marker1 })`);
-      await page.evaluate(`window.term.registerDecoration({ marker: window.marker2 })`);
-      await openTerminal(page);
-      await pollFor(page, `document.querySelectorAll('.xterm-screen .xterm-decoration').length`, 2);
+  describe('registerDecoration', () => {
+    describe('bufferDecorations', () => {
+      it('should register decorations and render them when terminal open is called', async () => {
+        await page.evaluate(`window.term = new Terminal({})`);
+        await page.evaluate(`window.term.open(document.querySelector('#terminal-container'))`);
+        await page.waitForSelector('.xterm-text-layer');
+        await page.evaluate(`window.marker1 = window.term.addMarker(1)`);
+        await page.evaluate(`window.marker2 = window.term.addMarker(2)`);
+        await page.evaluate(`window.term.registerDecoration({ marker: window.marker1 })`);
+        await page.evaluate(`window.term.registerDecoration({ marker: window.marker2 })`);
+        await openTerminal(page);
+        await pollFor(page, `document.querySelectorAll('.xterm-screen .xterm-decoration').length`, 2);
+      });
+      it('should return undefined when the marker has already been disposed of', async () => {
+        await openTerminal(page);
+        await page.evaluate(`window.marker = window.term.addMarker(1)`);
+        await page.evaluate(`window.marker.dispose()`);
+        await pollFor(page, `window.decoration = window.term.registerDecoration({ marker: window.marker });`, undefined);
+      });
+      it('should throw when a negative x offset is provided', async () => {
+        await openTerminal(page);
+        await page.evaluate(`window.marker = window.term.addMarker(1)`);
+        await page.evaluate(`
+        try {
+          window.decoration = window.term.registerDecoration({ marker: window.marker, x: -2 });
+        } catch (e) {
+          window.throwMessage = e.message;
+        }
+      `);
+        await pollFor(page, 'window.throwMessage', 'This API only accepts positive integers');
+      });
     });
-    it('should return undefined when the marker has already been disposed of', async () => {
-      await openTerminal(page);
-      await page.evaluate(`window.marker = window.term.addMarker(1)`);
-      await page.evaluate(`window.marker.dispose()`);
-      await pollFor(page, `window.decoration = window.term.registerDecoration({ marker: window.marker });`, undefined);
-    });
-    it('should throw when a negative x offset is provided', async () => {
-      await openTerminal(page);
-      await page.evaluate(`window.marker = window.term.addMarker(1)`);
-      await page.evaluate(`
-      try {
-        window.decoration = window.term.registerDecoration({ marker: window.marker, x: -2 });
-      } catch (e) {
-        window.throwMessage = e.message;
-      }
-    `);
-      await pollFor(page, 'window.throwMessage', 'This API only accepts positive integers');
+    describe('overviewRulerDecorations', () => {
+      it('should not add an overview ruler when width is not set', async () => {
+        await page.evaluate(`window.term = new Terminal({})`);
+        await page.evaluate(`window.term.open(document.querySelector('#terminal-container'))`);
+        await page.waitForSelector('.xterm-text-layer');
+        await page.evaluate(`window.marker1 = window.term.addMarker(1)`);
+        await page.evaluate(`window.marker2 = window.term.addMarker(2)`);
+        await page.evaluate(`window.term.registerDecoration({ marker: window.marker1, overviewRulerOptions: { color: 'red' } })`);
+        await page.evaluate(`window.term.registerDecoration({ marker: window.marker2, overviewRulerOptions: { color: 'blue' } })`);
+        await openTerminal(page);
+        await pollFor(page, `document.querySelectorAll('.xterm-decoration-overview-ruler').length`, 0);
+      });
+      it('should add an overview ruler when width is set', async () => {
+        await page.evaluate(`window.term = new Terminal({ overviewRulerWidth: 15 })`);
+        await page.evaluate(`window.term.open(document.querySelector('#terminal-container'))`);
+        await page.waitForSelector('.xterm-text-layer');
+        await page.evaluate(`window.marker1 = window.term.addMarker(1)`);
+        await page.evaluate(`window.marker2 = window.term.addMarker(2)`);
+        await page.evaluate(`window.term.registerDecoration({ marker: window.marker1, overviewRulerOptions: { color: 'red' } })`);
+        await page.evaluate(`window.term.registerDecoration({ marker: window.marker2, overviewRulerOptions: { color: 'blue' } })`);
+        await openTerminal(page);
+        await pollFor(page, `document.querySelectorAll('.xterm-decoration-overview-ruler').length`, 1);
+      });
     });
   });