adding support for percyThrowErrorOnFailure , by default it will be f…

…alse (#803)

* adding support for throwErrorOnFailure, by default it will be false

* update readme and test fux

* test fix

* test fix

* test fix

* ignoring the thowing of error

* ignoring throwing error from cypress

* adding PERCY_THROW_ERROR_ON_FAILURE variable as a global on cypress env

* adding PERCY_THROW_ERROR_ON_FAILURE on config level

* adding test on failure

README.md

@@ -66,6 +66,14 @@ $ percy exec -- cypress run
 - `name` - The snapshot name; must be unique to each snapshot; defaults to the full test title
 - `options` - [See per-snapshot configuration options](https://docs.percy.io/docs/cli-configuration#per-snapshot-configuration)
 
+## Cypress Config
+- `percyThrowErrorOnFailure` - If set to true, it will throw an error when one is encountered. By default, it is set to false, and errors are suppressed.
+If you are using uncaught exeception then test test will pass.
+```
+cy.on("uncaught:exception", (e, runnable) => {});
+
+```
+
 ## Upgrading
 
 ### Automatically with `@percy/migrate`

cypress/e2e/index.cy.js

@@ -42,6 +42,35 @@ describe('percySnapshot', () => {
     ]);
   });
 
+  describe('if percyThrowErrorOnFailure set to true', () => {
+    let ogPercyThrowErrorOnFailure;
+
+    beforeEach(() => {
+      ogPercyThrowErrorOnFailure = Cypress.config('percyThrowErrorOnFailure');
+    });
+
+    afterEach(() => {
+      Cypress.config().percyThrowErrorOnFailure = ogPercyThrowErrorOnFailure;
+    });
+
+    it('disables snapshots and fails the test', () => {
+      cy.on('fail', (_err, runnable) => {
+        // it only runs when test fails.
+        // This will supress failure and pass the test.
+        return false;
+      });
+
+      Cypress.config().percyThrowErrorOnFailure = true;
+      cy.then(() => helpers.test('error', '/percy/snapshot'));
+
+      cy.percySnapshot();
+
+      cy.then(() => helpers.logger.stderr).should('include.members', [
+        '[percy] Could not take DOM snapshot "percySnapshot handles snapshot failures"'
+      ]);
+    });
+  });
+
   describe('in interactive mode', () => {
     let ogInteractive;
 

index.js

@@ -73,6 +73,9 @@ Cypress.Commands.add('percySnapshot', (name, options) => {
         // Handle errors
         log.error(`Could not take DOM snapshot "${name}"`);
         log.error(error);
+        if (Cypress.config('percyThrowErrorOnFailure')) {
+          throw error;
+        }
       });
     });
   });