Mixing
Why does Jest coverage (Istanbul) measure 0 branches in this Vue component method?
Please consider the following - somewhat contrived - Vue component:
<!-- FooBar.vue -->
<template>
<div @click="onClick">{{text}}</div>
</template>
<script>
export default {
name: 'foo-bar',
data() {
return {
text: 'foo'
}
},
methods: {
onClick() {
this.text = 'bar';
}
}
}
</script>
I've covered the component with a Jest unit test like so:
// FooBar.spec.js
import FooBar from '~/FooBar.vue';
import { shallowMount } from '@vue/test-utils';
import { expect } from 'chai';
describe('FooBar onClick()', () => {
it('should change the text to "bar"', () => {
// Arrange
const target = shallowMount(FooBar);
// Act
target.trigger('click');
// Assert
const div = target.find('div');
expect(div.text()).to.equal('bar');
});
});
The test passes green.
When I run Jest with --coverage for this file, I get the following summary report:
=============================== Coverage summary ===============================
Statements : 0.1% ( 2/1868 )
Branches : 0% ( 0/1402 )
Functions : 0% ( 0/505 )
Lines : 0.2% ( 2/982 )
================================================================================
As you can see, the number of branches covered by the unit test is shown to be 0 - Even though Jest (or more accurately Instanbul, which Jest uses behind the scenes for coverage) did detect that the test covered two lines of code.
When I've made a tiny experiment and added an if statement inside onClick() like so:
onClick() {
if (this.text != undefined) {
this.text = 'bar';
}
}
then Jest did indeed count 1 branch covered.
My question is - Why does Jest / Istanbul not count the code in the onClick() as a branch covered?
javascript vue.js jestjs istanbul
asked Jan 1 at 19:39
urigurig
6,4881464118
add a comment |
Please consider the following - somewhat contrived - Vue component:
<!-- FooBar.vue -->
<template>
<div @click="onClick">{{text}}</div>
</template>
<script>
export default {
name: 'foo-bar',
data() {
return {
text: 'foo'
}
},
methods: {
onClick() {
this.text = 'bar';
}
}
}
</script>
I've covered the component with a Jest unit test like so:
// FooBar.spec.js
import FooBar from '~/FooBar.vue';
import { shallowMount } from '@vue/test-utils';
import { expect } from 'chai';
describe('FooBar onClick()', () => {
it('should change the text to "bar"', () => {
// Arrange
const target = shallowMount(FooBar);
// Act
target.trigger('click');
// Assert
const div = target.find('div');
expect(div.text()).to.equal('bar');
});
});
The test passes green.
When I run Jest with --coverage for this file, I get the following summary report:
=============================== Coverage summary ===============================
Statements : 0.1% ( 2/1868 )
Branches : 0% ( 0/1402 )
Functions : 0% ( 0/505 )
Lines : 0.2% ( 2/982 )
================================================================================
As you can see, the number of branches covered by the unit test is shown to be 0 - Even though Jest (or more accurately Instanbul, which Jest uses behind the scenes for coverage) did detect that the test covered two lines of code.
When I've made a tiny experiment and added an if statement inside onClick() like so:
onClick() {
if (this.text != undefined) {
this.text = 'bar';
}
}
then Jest did indeed count 1 branch covered.
My question is - Why does Jest / Istanbul not count the code in the onClick() as a branch covered?
javascript vue.js jestjs istanbul
asked Jan 1 at 19:39
urigurig
6,4881464118
add a comment |
Please consider the following - somewhat contrived - Vue component:
<!-- FooBar.vue -->
<template>
<div @click="onClick">{{text}}</div>
</template>
<script>
export default {
name: 'foo-bar',
data() {
return {
text: 'foo'
}
},
methods: {
onClick() {
this.text = 'bar';
}
}
}
</script>
I've covered the component with a Jest unit test like so:
// FooBar.spec.js
import FooBar from '~/FooBar.vue';
import { shallowMount } from '@vue/test-utils';
import { expect } from 'chai';
describe('FooBar onClick()', () => {
it('should change the text to "bar"', () => {
// Arrange
const target = shallowMount(FooBar);
// Act
target.trigger('click');
// Assert
const div = target.find('div');
expect(div.text()).to.equal('bar');
});
});
The test passes green.
When I run Jest with --coverage for this file, I get the following summary report:
=============================== Coverage summary ===============================
Statements : 0.1% ( 2/1868 )
Branches : 0% ( 0/1402 )
Functions : 0% ( 0/505 )
Lines : 0.2% ( 2/982 )
================================================================================
As you can see, the number of branches covered by the unit test is shown to be 0 - Even though Jest (or more accurately Instanbul, which Jest uses behind the scenes for coverage) did detect that the test covered two lines of code.
When I've made a tiny experiment and added an if statement inside onClick() like so:
onClick() {
if (this.text != undefined) {
this.text = 'bar';
}
}
then Jest did indeed count 1 branch covered.
My question is - Why does Jest / Istanbul not count the code in the onClick() as a branch covered?
javascript vue.js jestjs istanbul
asked Jan 1 at 19:39
urigurig
6,4881464118
Please consider the following - somewhat contrived - Vue component:
<!-- FooBar.vue -->
<template>
<div @click="onClick">{{text}}</div>
</template>
<script>
export default {
name: 'foo-bar',
data() {
return {
text: 'foo'
}
},
methods: {
onClick() {
this.text = 'bar';
}
}
}
</script>
I've covered the component with a Jest unit test like so:
// FooBar.spec.js
import FooBar from '~/FooBar.vue';
import { shallowMount } from '@vue/test-utils';
import { expect } from 'chai';
describe('FooBar onClick()', () => {
it('should change the text to "bar"', () => {
// Arrange
const target = shallowMount(FooBar);
// Act
target.trigger('click');
// Assert
const div = target.find('div');
expect(div.text()).to.equal('bar');
});
});
The test passes green.
When I run Jest with --coverage for this file, I get the following summary report:
=============================== Coverage summary ===============================
Statements : 0.1% ( 2/1868 )
Branches : 0% ( 0/1402 )
Functions : 0% ( 0/505 )
Lines : 0.2% ( 2/982 )
================================================================================
As you can see, the number of branches covered by the unit test is shown to be 0 - Even though Jest (or more accurately Instanbul, which Jest uses behind the scenes for coverage) did detect that the test covered two lines of code.
When I've made a tiny experiment and added an if statement inside onClick() like so:
onClick() {
if (this.text != undefined) {
this.text = 'bar';
}
}
then Jest did indeed count 1 branch covered.
My question is - Why does Jest / Istanbul not count the code in the onClick() as a branch covered?
javascript vue.js jestjs istanbul
javascript vue.js jestjs istanbul
asked Jan 1 at 19:39
urigurig
6,4881464118
asked Jan 1 at 19:39
urigurig
6,4881464118
edited Jan 1 at 19:45
urig
asked Jan 1 at 19:39
urigurig
6,4881464118
asked Jan 1 at 19:39
urigurig
6,4881464118
asked Jan 1 at 19:39
urigurig
6,4881464118
6,4881464118
add a comment |
add a comment |
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