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In this video, we leverage the test context we created in the previous video and begin writing the tests for a service that accesses an external API.
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git checkout -f v8
Using Git with this Workshop
See the README on Github for information on how to use Git with this repo to follow along with this workshop.
With our test contacts ready to rock,
let's get to writing these tests.
0:00
The first thing we'll do is Autowire
our service under test that is
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the Weather Service.
0:08
So I'll create an Autowired field here
Weather Service, and I'll name it service.
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Next, let's tell about our test methods.
0:17
Now, we could go crazy testing the service
that utilizes the external forecast at
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IO API.
0:24
Here, we'll just test a few pieces
of the actual API response.
0:26
First, we'll make sure that the latitude
and longitude that come back
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from the API response match what
we included in the request.
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The reason I'm doing this is because I
want to make sure that the forecast data
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I'm getting back is actually for
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the location I requested and
not some other location.
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So, here's that method stub.
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We'll say it's a test method.
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Public void, and we want to test if
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findByLocation_ShouldReturnSameCoords.
0:53
Next, let's make sure we get back
eight days of forecast data.
1:02
So next, I'll right a test method
that's called findByLocation, and
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it should return 8DaysForecastData.
1:15
Now, that's today and the next seven days.
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Cool.
1:28
And finally,
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let's make a test that ensures we
can get back our current conditions.
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So, this test method,
will be called public
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void
findByLocation_ShouldReturnCurrentCondit-
1:40
ions Great.
1:46
Now keep in mind that the purpose
of these tests isn't so
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much to ensure that the weather API works,
that's for the developers of that API.
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Rather this is to ensure that
our application properly
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captures those results and sticks
the results into the proper objects.
2:01
Okay, that said,
let's start in on the first method.
2:06
So that should be
the findByLocation_ShouldReturnSameCoords.
2:10
Since we'll need a set of latitude and
longitude coordinates to make these
2:14
requests, let's create a field for
that and set it up in the before method.
2:18
So right here, I'll say private
Location and abbreviate it loc.
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Of course the wild thing to do
would be to name it Tone Loc.
2:29
Anyway let's import this and
go here hit option enter and
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want to make sure I pick
my object right here.
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There it is cool.
2:42
And let's create a before
method to set that up.
2:44
Before.
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So public void set up sometimes
you'll see this U capitalized.
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Doesn't really matter as long
as it's annotated with before.
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And we'll say loc = new Location and you
can pass in whatever coordinates you like.
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I've got a set of coordinates that point
to Chicago, somewhere in Chicago at least.
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9403795.
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And -87.6531804 and
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then a bunch of 9's.
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Cool, and as we're fetching the data,
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we're going to get back a weather object
so let's create a field for that and
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make the service call that
stores a weather object into it.
3:31
So the field, I'll make right
here private Weather weather,
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and I will make that
service call right here.
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Since in all of these tests I'm going to
be making a call to that find by location
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method of the service.
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So I'll say,
weather = service.findByLocation and
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I'll pass it loc or Tone Loc,
whatever you named it.
3:54
Now, to test the coordinates in
the test method, I'll use Hamcrest and
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test the latitude and
longitude separately.
4:03
So in here I will assertThat and
we'll say that the weather.getlatitude and
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let's get that assertThat
method imported here and
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that comes from hamcrest right here.
4:19
Cool.
4:22
I want to assert that weather.getlatitude
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is close to the latitude that
I made the API call with.
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Now since geo coordinates
may not be exact,
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we can use a handy hamcrest
matcher called close to.
4:34
That checks whether or not the actual
value is close to an expected value
4:38
within a specified margin of error.
4:42
And since I'll be reusing this
margin of error for longitude,
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I'll quickly create a class field for
that.
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So up here,
I'll say private static final double.
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I'll call it ERROR_GEO.
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Zero point, I don't know,
I'll make it a reasonably precise value.
5:00
And now here's how we
use that CloseTo method.
5:06
So, I'll say, closeTo, okay,
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loc.getLongitude, ERROR_GEO.
5:16
Okay, now we need to import
this closeTo method.
5:23
So, that's a static import of the
matchers.closeTo method and there we go.
5:25
We want to assert that this latitude that
we get back in the weather object which is
5:32
a result of the service call, we want
to assert that the latitude is closeTo
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the longitude we made the call
with within this margin of error.
5:44
Of course,
we wanna check latitude with latitude.
5:49
So I should probably
change this to latitude.
5:51
Cool.
5:53
Now let's copy and
paste this for longitude.
5:55
So I'll copy this and I will paste this,
changing it to longitude.
5:57
All right, let's see if this
thing runs with our test context.
6:06
So, again, with the editor in focus,
I'll hit control, shift, R.
6:08
Now, you'll see a little more output
this time as spring loads only
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the specified components
from your test context.
6:16
And, great.
6:19
Still green.
6:20
Next test.
6:22
Let me collapse this.
6:23
And in our next test, let's assert that
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we get eight days of forecast data.
6:30
So we want to assert that when
we get the daily forecast data,
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that this list has the size of eight.
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Lots of stuff you can do with
these Hamcrest matchers.
6:47
Again, these matchers are really
nice in that you can create some
6:50
cool readable code here.
6:53
So we're going to assert that
this list has this size.
6:55
Okay, let's run that again.
7:01
Again, you'll see a lot of output from
your test context being loaded and
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it looks like indeed our second test
passed on to the last method here.
7:10
For this one, we wanna make sure that
the data we get back is time stamped with
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the current time within
a reasonable margin of error.
7:20
Let's create a field for
that error margin too,
7:23
and this one will be
expressed in milliseconds.
7:25
So, I'll go right below this one,
and I'll say private static final
7:28
double ERROR_TIME this time.
7:32
And again it's in milliseconds.
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So, say as long as it's in within five
seconds then I'll be cool with that.
7:38
Now the way will do this is that
will first grab the current time
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as an instant object.
7:46
So we’ll say instant.
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I'll call it now equals Instant.now.
7:50
Excellent.
7:53
Then we'll calculate the duration
between that instant and
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the instant from the weather
data returned by the service.
7:58
So let's create a variable for that.
8:01
So the duration will say
as duration.between.
8:03
We'll say it's between now and
8:08
weather.getCurrently().getTime and
8:11
we will convert that to milliseconds,
toMillis().
8:17
So we're going to get
the duration between now and
8:23
whatever time stamp comes back
expressed in milliseconds.
8:27
Storing that into the double
variable we have named duration.
8:31
And finally, we will assertThat the
duration, again using this closeTo method,
8:35
the duration is close to 0
within this margin of error.
8:42
All righty, with our final
piece of test code written for
8:48
the weather service,
let's fire it up one more time.
8:51
Our test contacts loading and
it looks like all three tests passed.
8:56
Boom, hey we're seeing
a lot of green today, but
9:02
I guarantee you that the grass
isn't always this green.
9:04
There might be a lot of red as you try
to get these working on your machine,
9:08
whether it's for
this project or for another.
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But hey keep at it.
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You'll eventually get there.
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