More explicit assert with hamjest

Wolfram Kriesing - January 31, 2017 - tagged with: #testing #assertion #tdd #knowledgebase

An undone blog post - More explicit assert with hamjest

it('is true for a day that is a specialDay', () => { const isSpecialDay = specialDays()[2].isSpecialDay; assertThat(isSpecialDay, equalTo(true)); });

it('provides the special day's name', () => { const specialDay = specialDays()[2].specialDay; assertThat(specialDay, equalTo({ name: specialDayName })); });

vs.

it('is true for a day that is a specialDay', () => { const day = specialDays()[2]; assertThat(day, hasProperty('isSpecialDay', equalTo(true))); });

it('provides the special day's name', () => { const day = specialDays()[2]; assertThat(day, hasProperty('specialDay', equalTo({ name: specialDayName }))); });

there is even a simple transformation in it

assertThat(isSpecialDay, equalTo(true));

transforms into

assertThat(day.isSpecialDay, equalTo(true));

makes it obvious, that when the lookup day.isSpecialDay fails we will get an error message like undefined does not equal to true :( so let's tranform it into

assertThat(day, hasProperty('isSpecialDay', equalTo(true)));

and we will get: day has no property isSpecialDay which should equal to true

You might say, that's two assertion in on test, but I am fine with that as long as the test reporter tells me all the things that are wrong. Otherwise I would have to figure out in which order to solve failing tests.