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In this lecture, we are going to add a custom error message for our tests.

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From my experience, Jasmine outputs uninformative unhelpful error messages.

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Let's look at an example in your editor.

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Open the test file for the tabs container components.

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Previously we created to test assertions from within a single test file.

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Let's say that both tests fail.

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For example, I'm going to change the value in the to b functions to three.

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This update should cause the tests to fail.

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Let's check out the browser according to the description for the error messages, Jazmin expected two

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but got three.

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That's not very helpful.

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The description doesn't help us debug the problem with our application.

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Luckily we can add custom error messages to each test assertion.

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Head back to the editor.

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Adding error messages can be helpful if you have multiple test assertions.

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What if one assertion passed but the other failed?

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How would we know which assertion passed?

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Our messages should give a clear, concise picture of the problem.

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For the first assertion, let's chain a function called with context after the expected function.

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The with context function must always be applied after calling the expect function, but before the

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matcher, this function allows us to write a custom error message for the assertion.

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Let's write the following message tabs did not render.

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If this test failed, our query failed to select the elements in the template.

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Our message should reflect that results.

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Next, let's chain another with context function to the second test assertion.

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This time the function will output.

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The following error message could not grab component property.

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Let's check out the browser.

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Our error messages appear on the page.

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These messages are more helpful than the default messages.

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Whenever possible, I always recommend writing custom messages.

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If you're creating multiple assertions, it can help you understand the problem with your test or application.

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Before ending this lecture, I'm going to revert the values in the to b function.

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We don't want our tests to fail anymore.

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Once you've updated your tests, I'll see you in the next lecture.