kuhlenh / EmeraldTransit

Demo Instructions

You can see the whole talk on Ch9 or YouTube.

Setup

1. Install Visual Studio 2017 15.8
2. Download source code for demo
3. Have a breakpoint on the open brace of GetArrivalTimesForRouteName(...) (MyStopInfo, line 150)
4. Tools>Options>Text Editor>C#>Advanced>Enable navigation to decompiled assemblies
5. Visual Studio Live Share
6. Visual Studio IntelliCode

Demo Steps

Phase I

1. Open solution and show how quickly Test Explorer discovers unit tests

   Note: responsive icons which show pending, running, and completed test runs

   • Show off the new hierarchy view to organize tests by project, namespace, and class

2. Right-click and debug failing test, TestGetArrivals()

3. Hit the breakpoint in GetArrivalTimesForRouteName(...) (MyStopInfo, line 150).

   • F10 and F11 to step over and into

   • Use Run To Click to run debugger execution to mouse

   • Step until var busTimes = arrivalData .Where(a=> a.PredictedArrivalTime != null && (Int64)a.PredictedArrivalTime > 0) .Select(a => BusHelpers.ConvertMillisecondsToUTC(a.PredictedArrivalTime));. Put a breakpoint on the BusHelpers expression with F9.

     Note: this is external source

   • Press Shift+F5 to continue debugging until it hits that breakpoint. Use Navigation to decompiled assemblies to see the definition of BusHelpers.ConvertMillisecondsToUTC(...). We worked with ILSpy team to build in a decompiler to see method bodies, not just signatures.

   • Even better to see the real source. Use F11 to Step Into BusHelpers.ConvertMillisecondsToUTC and SourceLink will download your source on the fly while debugging. Step through the whole method, inspect variables, etc.

     Note: TestGetArrivals() isn't failing because of external source.

4. Step inside the foreach until you get to after the delta calculation. Here we can see delta.TotalMinutes is a very long decimal.

   • Use Edit and Continue to select delta.TotalMinutes, introduce a local variable with Ctrl+., and use Math.Round(..., 0) to round the result. Stepping through the next value in the foreach will show that this correctly rounded the total minutes.

5. Go back to Test Explorer and re-run your tests. See that TestGetArrivals() is now passing.

   Note: tests are organized alphabetically rather than pass/fail. This is so you can track your changes more easily.

Phase II

1. We still have a failing test, TestGetArrivalsNull(). Double-click the test in Test Explorer to navigate to the test. By using CodeLens, we can see that Allison touched this test last.
2. Call Allison and start a Live Share session by clicking the Share button in the top-right of VS. Send the link copied to your clipboard to Allison.
3. Turn on Live Unit Testing via Test > Live Unit Testing > Start.
   • Live Unit Testing removes all the manual steps we just did in Phase I with unit testing by automatically figuring out which tests are impacting by our code changes, running only those tests, and updating icons in the editor so we don't lose the context of our development.
   • Red X = at least one failing test hits this line; Green Check = all passing tests hit this line; Blue Dash = no unit tests hit this line
   • Click an icon to see what tests hit the line, hover to see Exception info, and double-click to navigate to test.
4. The host of the LiveShare session starts debugging the test TestGetArrivalsNull(). The guest of LiveShare can now step over and then into GeocodeHelpers.ValidateLatLon(lat, lon). From here, they will hit an Exception and see the Exception Helper.
   • We know that lat is null from our Helper. Go to the parameter list and press Ctrl+. and add a null check.
   • On the host's machine, we can see that Live Unit Testing has updated live and let us know our tests are now passing.
5. End the Live Share session.

Phase III

1. Running this Alexa skill at home, I realized it wasn't giving me bus times for the cloeset bus stop to me. Use Go To All with Ctrl+T to quickly navigate to files/types/symbols/members. Type getloc and navigate to method GetRouteAndStopForLocation.
2. This line lets us know that no calculations were done Stop minDistStop = stops.First();, we just grab the first bus stop returned.
3. Use Ctrl+K,C to comment out that line.
4. Write some new code to find the closest bus stop:

 var min = (from stop in stops
            select GeocodeHelpers.CalculateDistanceFormula(lat, stop.Lat, lon, stop.Lon)).Min();
 Stop minDistStop = stops.Where(x => GeocodeHelpers.CalculateDistanceFormula(lat, x.Lat, lon, x.Lon) == min).FirstOrDefault();

1. Use Ctrl+. to generate the missing method GeocodeHelpers.CalculateDistanceFormula. Use Ctrl+Click to create a hyperlink on the GeocodeHelpers.CalculateDistanceFormula symbol to Go To Definition.
   • Change the return type of the method to double
   • Use Ctrl+. to Change Method Signature and reorder parameters so that the location pairs are organized by type
   • Inside the method body, type var distance = Math.. See the IntelliCode suggestions.
   • Now change var to double and use Ctrl+Space to bring up completion again and show a different list based on the new context

Phase IV

1. Live Unit Testing hasn't changed despite me changing my code...meaning I don't have a unit test that properly tests this scenario.
2. From the editor, select the CalculateDistanceFormula and use Ctrl+E,E to send the code snippet to the C# Interactive Window
   • Execute the following statements:

(string lat, string lon) conventionCenter = ("47.611959", "-122.332893");
(double lat, double lon) NewStop = (47.61196, -122.33489);
(double lat, double lon) MyStop = (47.613937, -122.33416);

• Execute CalculateDistanceFormula(conventionCenter.lat, conventionCenter.lon, MyStop.lat, MyStop.lon). Press Ctrl+Enter to force excecution when your cursor is not at the end of the line.
• Use Alt+Up to access Interactive history and change MyStop to NewStop and commit again.

Note that the new bus stop you're going to add to the json file is indeed a closer bus stop

1. Use Ctrl+T and type "json" to navigate to file StopsForLoc.json
2. Add the following to the list of bus stops:

{
        "code": '"700"',
        "direction": '"NW"',
        "id": '"Testing-1-2-3"',
        "lat": 47.611960,
        "locationType": 0,
        "lon": -122.332893,
        "name": '"NewStop"',
        "routeIds": [ "1_100264", "40_100236" ],
        "wheelchairBoarding": '"UNKNOWN"'
}

• Notice that the json is invalid because of escaped characters. Use multi-caret mode commands to fix.
• Select "\ and press Shift+Alt+Ins to add new selections of escaped characters and Delete (make sure Fn is not on!)
• Now select \" and use Ctrl+Ins to select all instances of escaped characters and delete.

1. Go back to file MyStopInfo.cs and see that Live Unit Testing is reporting failures. Investigating a red X and hovering over a failing tests shows the "Testing1-2-3" that we just added, so our method is correctly returning the closest stop.
2. Delete that new stop...to make tests pass again.
3. Use Team Explorer status bar to see git status. Commit recent changes.

Phase V

1. Go to GeocodeHelpers.cs and look at the dotted suggestions in the file
2. Show that you can use Ctrl+. to apply a code suggestion with a lightbulb, or you can apply the opposite as a refactoring (e.g., flip between implicit and explicit types)
3. Right-click in Solution Explorer and Add > New Item. Type "editorconfig"

• We now have starter templates in here
• Use VS IntelliCode to generate an .editorconfig based on your current coding conventions in your codebase

Note: You no longer need to close and reopen all files to see changes from an edited .editorconfig

1. Open the Error List and filter to just "Current Document"
2. Go to Tools>Options>Text Editor>C#>Code Style>Formatting to see new Format Document cleanup configuraiton
3. Change settings and click 'OK'
4. Format Document with Ctrl+K,D* and see all the errors in Error List disappear!

Phase VI

1. Everyone wants more refactorings, so here is a tour de source
2. Go to Error List and show Warnings in whole solution. See "unreachable code". Navigate and use Ctrl+. to remove unreachable code.
3. Convert if to switch
4. Add missing switch cases
5. Convert to interpolated string
6. Add missing accessibility modifiers
7. Make readonly
8. Order modifiers
9. Convert LINQ to foreach, foreach to for
10. Invert if