puppeteer: Add run_test method to common.

This method does all error handling and removes ~5-6 lines of try/catch
block across each test file.

frontend_tests/puppeteer_lib/common.js

@@ -28,6 +28,18 @@ class CommonUtils {
 
         return page;
     }
+
+    async run_test(test_function) {
+        try {
+            await test_function();
+        } catch (e) {
+            console.log(e);
+            await this.browser.close();
+            process.exit(1);
+        } finally {
+            this.browser.close();
+        }
+    }
 }
 
 const common = new CommonUtils();

frontend_tests/puppeteer_tests/00-realm-creation.js

@@ -7,7 +7,6 @@ const organization_name = 'Awesome Organization';
 const host = "zulipdev.com:9981";
 
 async function run() {
-    try {
     const page = await common.get_page('http://' + host + '/new/');
 
     // submit the email for realm creation.
@@ -44,12 +43,6 @@ async function run() {
     // Check if realm is created and user is logged in by checking if
     // element of id `lightbox_overlay` exists.
     await page.waitForSelector('#lightbox_overlay');  // if element doesn't exist,timeout error raises
-    } catch (e) {
-        console.log(e);
-        process.exit(1);
-    } finally {
-        common.browser.close();
-    }
 }
 
-run();
+common.run_test(run);

frontend_tests/puppeteer_tests/01-login.js

@@ -24,14 +24,8 @@ async function log_out(page) {
 
 async function run() {
     const page = await common.get_page(realm_url + 'login/');
-    try {
     await log_in(page, test_credentials.default_user);
     await log_out(page);
-    } catch (e) {
-        console.log(e);
-        process.exit(1);
-    } finally {
-        common.browser.close();
 }
-}
-run();
+
+common.run_test(run);