1
00:00:01,630 --> 00:00:04,980
In this video we're going to take a look at some the different libraries and processes that we're going

2
00:00:04,970 --> 00:00:07,410
to go through to implement all this testing stuff.

3
00:00:07,480 --> 00:00:13,060
Now as a reminder we're going to really be focusing on this testing goal number one or hour off service.

4
00:00:13,190 --> 00:00:17,710
So we're going to write out some tests that are going to try to send a request off to our service and

5
00:00:17,710 --> 00:00:23,250
then make some assertion about the response or make sure that some data was written into Mongo DB.

6
00:00:23,290 --> 00:00:28,540
We are not going to be worried right now about writing some tests or on models or event admitting and

7
00:00:28,540 --> 00:00:29,650
receiving.

8
00:00:29,690 --> 00:00:29,950
OK.

9
00:00:29,980 --> 00:00:34,650
So with all that in mind let's take a look at how we're going to wire up all this testing stuff.

10
00:00:34,810 --> 00:00:38,050
We're going to add in a new script to our package not just on file.

11
00:00:38,050 --> 00:00:43,580
Whenever we run the command and run test we are going to start up a test runner called jest.

12
00:00:43,780 --> 00:00:49,570
So just as the library that we're going to use to actually execute tests inside of our project then

13
00:00:49,660 --> 00:00:55,220
on the right hand side this is pretty much what we're going to have just do the wind just starts running.

14
00:00:55,270 --> 00:01:00,690
We're going to tell just to do the following things you see over here first off we're gonna start up

15
00:01:00,750 --> 00:01:02,980
in in memory copy of Mongo DB.

16
00:01:03,540 --> 00:01:06,720
So this is gonna be a copy of Mongo that's running in memory.

17
00:01:06,720 --> 00:01:11,250
In other words it will not be you do not have to install Margo directly onto your machine.

18
00:01:11,250 --> 00:01:14,930
Now even if you already have Mongo installed on your local machine we are still going to use this in

19
00:01:14,930 --> 00:01:15,970
memory copy.

20
00:01:15,990 --> 00:01:20,250
There's a couple of reasons for that and we'll go through them as we start to wire up the in-memory

21
00:01:20,250 --> 00:01:28,010
copy after that we're gonna start up our Express app and then we'll use a library called super test

22
00:01:28,160 --> 00:01:33,090
to make fake requests to our Express application and then after that we will run some assertions to

23
00:01:33,090 --> 00:01:36,000
make sure that the requested exactly what we expected it to do.

24
00:01:36,060 --> 00:01:40,860
So maybe respond respond to with some particular data or wrote some particular data to Mongo DB.

25
00:01:42,260 --> 00:01:44,510
Now I want to focus on this third step right here.

26
00:01:44,540 --> 00:01:50,630
The Super Test library in order to get Super Test working well we're going to do a little refactor to

27
00:01:50,630 --> 00:01:51,640
our project.

28
00:01:51,710 --> 00:01:56,630
So I want to show you some documentation around Super Test and help you understand why we're gonna do

29
00:01:56,630 --> 00:01:59,670
this refactor inside of a new browser tab.

30
00:01:59,700 --> 00:02:05,530
I'm going to open up the documentation for Super Test by going to NPM J ask.com and then doing a search

31
00:02:05,530 --> 00:02:06,850
for super test

32
00:02:09,770 --> 00:02:12,220
and here it is right here.

33
00:02:12,390 --> 00:02:17,570
I'm going to scroll down just a little bit and find the example section inside this example section.

34
00:02:17,620 --> 00:02:19,280
They've got a little bit of code right here.

35
00:02:19,480 --> 00:02:23,300
Now I took a screenshot of this code and put a diagram together around it.

36
00:02:23,380 --> 00:02:27,070
So I'm gonna go back over and take a look at that screenshot.

37
00:02:27,120 --> 00:02:31,830
So here's that little bit of code that's inside the read me and there's just something very important

38
00:02:31,830 --> 00:02:37,870
inside there that I want to point out right about in this section right here.

39
00:02:37,900 --> 00:02:41,400
They have some code to create an express server.

40
00:02:41,530 --> 00:02:45,050
Now at present you and I are doing that inside of our index not just file.

41
00:02:45,160 --> 00:02:50,350
Yes technically we create root handlers inside those other files and then we associate them all together

42
00:02:50,350 --> 00:02:56,290
inside the index such as file but we actually create our Express app like that express thing right there

43
00:02:56,470 --> 00:02:58,870
inside the index such as file.

44
00:02:58,870 --> 00:03:00,600
Why is that relevant.

45
00:03:00,610 --> 00:03:06,010
Well down here is how we use super tests to actually test our Express server.

46
00:03:06,100 --> 00:03:12,640
We have to get access to the Express application variable that is defined inside that index such as

47
00:03:12,640 --> 00:03:13,640
file.

48
00:03:13,900 --> 00:03:19,060
We're going to pass that express app into this request function that is coming from the Super Test library

49
00:03:19,770 --> 00:03:26,360
and then we can make a request and write out some expectations around it the whole thing I want to focus

50
00:03:26,360 --> 00:03:31,190
on here the whole big point I'm trying to make is that we are creating our Express application inside

51
00:03:31,190 --> 00:03:32,840
the index such as file.

52
00:03:32,840 --> 00:03:37,430
So at some point in time we're going to have to write out some code that's going to look a little bit

53
00:03:37,430 --> 00:03:38,320
like this.

54
00:03:38,360 --> 00:03:44,780
We're going to have to try to require the Express application from that index such as file over to some

55
00:03:44,840 --> 00:03:52,460
testing file just so we can get X access to that app variable there's a little problem with that inside

56
00:03:52,460 --> 00:03:53,760
of our index such as file.

57
00:03:53,780 --> 00:03:55,790
We have a lot of startup code.

58
00:03:55,790 --> 00:03:59,720
We have some code to tell the Express app to start listening on some given port.

59
00:03:59,720 --> 00:04:05,630
We also have some hard coded stuff to say tell mango or Mongoose to connect to our Mongo DB database

60
00:04:05,690 --> 00:04:08,020
on some particular U.R.L..

61
00:04:08,180 --> 00:04:14,450
So there are some very particular very hard coded startup logic inside of index dot J.S. but most in

62
00:04:14,450 --> 00:04:19,220
particular I want to focus on the fact that inside of index such s we automatically start listening

63
00:04:19,310 --> 00:04:21,770
on port three thousand inside there.

64
00:04:21,770 --> 00:04:23,210
Why is that relevant.

65
00:04:23,210 --> 00:04:28,430
Well at some point time you and I might want to be able to run multiple different tests on the same

66
00:04:28,430 --> 00:04:29,330
machine.

67
00:04:29,330 --> 00:04:36,360
In other words we might want to run some tests around our off service at the same time that we are running

68
00:04:36,360 --> 00:04:42,090
some tests around our order service the OSS service and the order service might both be trying to listen

69
00:04:42,140 --> 00:04:43,890
on port three thousand.

70
00:04:44,070 --> 00:04:50,760
So if we try to require in our Express app from that index not just file and both the off service and

71
00:04:50,760 --> 00:04:55,320
the ticket service or whatever else are listening on the same port we're gonna very quickly end up with

72
00:04:55,320 --> 00:05:00,120
an error and we will not be able to run tests from different services on the same machine at the same

73
00:05:00,120 --> 00:05:07,310
time just because they are both listening on the same port so to get around this and to allow us to

74
00:05:07,310 --> 00:05:10,550
run tests from multiple services on the same machine at the same time.

75
00:05:10,640 --> 00:05:16,340
We're going to rely upon some default behavior or some nice functionality inside a Super Test to back

76
00:05:16,340 --> 00:05:18,350
over here at the example section.

77
00:05:18,350 --> 00:05:22,910
You'll notice that it says if this server is not listening for connections then it will automatically

78
00:05:22,910 --> 00:05:25,670
start to listen on and ephemeral ports.

79
00:05:25,710 --> 00:05:30,590
A federal port right here just means that super test is going to pick a random available port on your

80
00:05:30,590 --> 00:05:34,440
computer and have the express app start to listen on that port.

81
00:05:34,640 --> 00:05:39,560
And so that feature right there will allow us to run tests from multiple different services at the same

82
00:05:39,560 --> 00:05:46,350
time and not have to worry about this port issue however if we want to take use of that functionality

83
00:05:46,380 --> 00:05:51,150
that means that inside of our index not just file we can not have any code that's going to have the

84
00:05:51,150 --> 00:05:54,900
express app automatically start to listen on port three thousand.

85
00:05:54,990 --> 00:05:56,700
So how are we going to fix this all up.

86
00:05:56,700 --> 00:05:57,690
Well here's what we're gonna do.

87
00:05:57,690 --> 00:06:02,850
Here's the refactor we're going to go through in the next video we're going to start to split out our

88
00:06:02,850 --> 00:06:06,580
index not just file into two different files.

89
00:06:06,720 --> 00:06:12,780
We're gonna create a new file called app J.S. inside about us we're going to create our Express application

90
00:06:12,990 --> 00:06:18,990
and export it the Express app that we create inside this file is not going to be listening on any port.

91
00:06:18,990 --> 00:06:26,160
So in other words we are not going to have any code inside of app J.S. that looks like this right here.

92
00:06:26,980 --> 00:06:31,550
We are not going to have anything inside this new app has filed it's going to have our app start listening

93
00:06:31,550 --> 00:06:33,920
on port three thousand or anything else.

94
00:06:34,010 --> 00:06:38,780
Instead we're just going to export the app after we have wired up all the appropriate middleware as

95
00:06:38,780 --> 00:06:45,090
root handlers and so on we're then going to export that thing into the test file where it can then be

96
00:06:45,090 --> 00:06:47,910
safely used by Super Test.

97
00:06:47,950 --> 00:06:54,000
We will also import it into a new index J.S. file and inside of index not J.S. is where we're going

98
00:06:54,000 --> 00:06:59,790
to have some actual code to start up our app and start listening on port three thousand so whenever

99
00:06:59,790 --> 00:07:03,400
we want to actually run our application inside of a dev or a production environment.

100
00:07:03,420 --> 00:07:07,020
In other words we never want to really start up our server for real.

101
00:07:07,020 --> 00:07:11,640
We're still going to execute the index not just file and nothing's just going to pull in the app that

102
00:07:11,640 --> 00:07:16,620
was declared over here but we're going to have the separate file that exports just the app itself so

103
00:07:16,620 --> 00:07:20,100
we can still use it safely inside that test file.

104
00:07:20,250 --> 00:07:21,170
OK.

105
00:07:21,510 --> 00:07:22,440
So that's pretty much it.

106
00:07:22,440 --> 00:07:26,960
I just want to help you understand why we are doing this refactor now at this point you might be saying

107
00:07:26,970 --> 00:07:31,920
Steven this seems like kind of a big refactor just to get the Super Test library working.

108
00:07:31,920 --> 00:07:36,780
Well it turns out that there are actually some huge benefits from creating our Express app inside of

109
00:07:36,780 --> 00:07:42,360
its own file and then doing some actual startup logic inside of this other file over here and you're

110
00:07:42,360 --> 00:07:47,670
gonna see some less benefits later on as we start to work on some of our other services.

111
00:07:47,670 --> 00:07:48,880
All right so a quick pause right here.

112
00:07:48,930 --> 00:07:50,970
We'll start to implement all this in the next video.