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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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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
0:04
the Weather Service.
0:08
So I'll create an Autowired field here
Weather Service, and I'll name it service.
0:09
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.
0:32
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.
0:40
So, here's that method stub.
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We'll say it's a test method.
0:46
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,
1:30
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
1:35
void
findByLocation_ShouldReturnCurrentCondit-
1:40
ions Great.
1:46
Now keep in mind that the purpose
of these tests isn't so
1:51
much to ensure that the weather API works,
that's for the developers of that API.
1:54
Rather this is to ensure that
our application properly
1:58
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.
2:22
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.
2:38
There it is cool.
2:42
And let's create a before
method to set that up.
2:44
Before.
2:47
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.
2:54
And we'll say loc = new Location and you
can pass in whatever coordinates you like.
2:57
I've got a set of coordinates that point
to Chicago, somewhere in Chicago at least.
3:04
9403795.
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And -87.6531804 and
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then a bunch of 9's.
3:21
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
3:44
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
4:00
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
4:13
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.
4:27
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.
4:55
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
5:37
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
6:13
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
6:26
we get eight days of forecast data.
6:30
So we want to assert that when
we get the daily forecast data,
6:35
that this list has the size of eight.
6:41
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
7:05
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.
7:37
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
7:54
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.
9:11
But hey keep at it.
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You'll eventually get there.
9:14
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