Fix firefox tests FitAddon tests

addons/xterm-addon-fit/src/FitAddon.api.ts

@@ -14,6 +14,8 @@ let page: Page;
 const width = 1024;
 const height = 768;
 
+let isFirefox = false;
+
 describe('FitAddon', () => {
   before(async function(): Promise<any> {
     this.timeout(20000);
@@ -25,6 +27,10 @@ describe('FitAddon', () => {
     await page.setViewport({ width, height });
     await page.goto(APP);
     await openTerminal(page);
+    // This is used to do conditional assertions since cell height is 1 pixel higher with the
+    // default font on Firefox. Minor differences in font rendering/sizing is expected so this is
+    // fine.
+    isFirefox = await page.evaluate(`navigator.userAgent.toLowerCase().indexOf('firefox') > -1`);
   });
 
   after(async () => {
@@ -45,7 +51,7 @@ describe('FitAddon', () => {
       await loadFit();
       assert.deepEqual(await page.evaluate(`window.fit.proposeDimensions()`), {
         cols: 87,
-        rows: 26
+        rows: isFirefox ? 28 : 26
       });
     });
 
@@ -53,7 +59,7 @@ describe('FitAddon', () => {
       await loadFit(1008);
       assert.deepEqual(await page.evaluate(`window.fit.proposeDimensions()`), {
         cols: 110,
-        rows: 26
+        rows: isFirefox? 28 : 26
       });
     });
 
@@ -75,14 +81,14 @@ describe('FitAddon', () => {
       await loadFit();
       await page.evaluate(`window.fit.fit()`);
       assert.equal(await page.evaluate(`window.term.cols`), 87);
-      assert.equal(await page.evaluate(`window.term.rows`), 26);
+      assert.equal(await page.evaluate(`window.term.rows`), isFirefox? 28 : 26);
     });
 
     it('width', async function(): Promise<any> {
       await loadFit(1008);
       await page.evaluate(`window.fit.fit()`);
       assert.equal(await page.evaluate(`window.term.cols`), 110);
-      assert.equal(await page.evaluate(`window.term.rows`), 26);
+      assert.equal(await page.evaluate(`window.term.rows`), isFirefox? 28 : 26);
     });
 
     it('small', async function(): Promise<any> {