bigmachine-io/taking-off

taking-off's Issues

So confused... debugging chapter

At the start of the Debugging chapter, before doing anything, I'm just trying to run the tests, and I'm getting the following when running "mix test --trace":

warning: variable "deps" does not exist and is being expanded to "deps()", please use parentheses to remove the ambiguity or change the variable name
  mix.exs:10

Compiling 6 files (.ex)
warning: variable "val" is unused
  lib/converter.ex:3

warning: variable "val" is unused
  lib/converter.ex:7

warning: variable "val" is unused
  lib/converter.ex:11

warning: variable "val" is unused
  lib/converter.ex:15

warning: variable "earth" does not exist and is being expanded to "earth()", please use parentheses to remove the ambiguity or change the variable name
  lib/physics/rocketry.ex:9

warning: variable "mars" does not exist and is being expanded to "mars()", please use parentheses to remove the ambiguity or change the variable name
  lib/physics/rocketry.ex:14

warning: variable "moon" does not exist and is being expanded to "moon()", please use parentheses to remove the ambiguity or change the variable name
  lib/physics/rocketry.ex:19

warning: variable "newtons_gravitational_constant" does not exist and is being expanded to "newtons_gravitational_constant()", please use parentheses to remove the ambiguity or change the variable name
  lib/physics/rocketry.ex:31

warning: variable "earth" does not exist and is being expanded to "earth()", please use parentheses to remove the ambiguity or change the variable name
  lib/physics/rocketry.ex:31

warning: variable "newtons_gravitational_constant" does not exist and is being expanded to "newtons_gravitational_constant()", please use parentheses to remove the ambiguity or change the variable name
  lib/physics/rocketry.ex:40

warning: variable "earth" does not exist and is being expanded to "earth()", please use parentheses to remove the ambiguity or change the variable name
  lib/physics/rocketry.ex:40

warning: variable "earth" does not exist and is being expanded to "earth()", please use parentheses to remove the ambiguity or change the variable name
  lib/physics/rocketry.ex:46

warning: variable "newtons_gravitational_constant" does not exist and is being expanded to "newtons_gravitational_constant()", please use parentheses to remove the ambiguity or change the variable name
  lib/physics/rocketry.ex:50

Generated physics app

PhysicsTest
  * test escape velocity of planet X is correct (0.00ms)

  1) test escape velocity of planet X is correct (PhysicsTest)
     test/physics_test.exs:19
     ** (FunctionClauseError) no function clause matching in Converter.to_km/1

     The following arguments were given to Converter.to_km/1:

         # 1
         926.9623828717426

     Attempted function clauses (showing 1 out of 1):

         def to_km(val) when -is_integer(val)-

     code: ev =  %{mass: 4.0e22, radius: 6.21e6} |> Physics.Rocketry.escape_velocity
     stacktrace:
       (physics) lib/converter.ex:27: Converter.to_km/1
       (physics) lib/physics/rocketry.ex:25: Physics.Rocketry.escape_velocity/1
       test/physics_test.exs:20: (test)

  * test Converter one works (0.00ms)
  * test ConverterTwo works (0.00ms)

  2) test ConverterTwo works (PhysicsTest)
     test/physics_test.exs:35
     ** (UndefinedFunctionError) function ConverterTwo.to_light_seconds/2 is undefined (module ConverterTwo is not available)
     code: ls = ConverterTwo.to_light_seconds({:miles, 1000}, precision: 5)
     stacktrace:
       ConverterTwo.to_light_seconds({:miles, 1000}, [precision: 5])
       test/physics_test.exs:36: (test)

  * test ConverterTwo works with default values (15.0ms)

  3) test ConverterTwo works with default values (PhysicsTest)
     test/physics_test.exs:40
     ** (UndefinedFunctionError) function ConverterTwo.to_light_seconds/1 is undefined (module ConverterTwo is not available)
     code: ls = ConverterTwo.to_light_seconds({:miles, 1000})
     stacktrace:
       ConverterTwo.to_light_seconds({:miles, 1000})
       test/physics_test.exs:41: (test)

  * test escape velocity of earth is correct (0.00ms)

  4) test escape velocity of earth is correct (PhysicsTest)
     test/physics_test.exs:4
     ** (FunctionClauseError) no function clause matching in Converter.to_km/1

     The following arguments were given to Converter.to_km/1:

         # 1
         11183.2516621689

     Attempted function clauses (showing 1 out of 1):

         def to_km(val) when -is_integer(val)-

     code: ev = Physics.Rocketry.escape_velocity(:earth)
     stacktrace:
       (physics) lib/converter.ex:27: Converter.to_km/1
       (physics) lib/physics/rocketry.ex:25: Physics.Rocketry.escape_velocity/1
       test/physics_test.exs:5: (test)

  * test escape velocity of moon is correct (0.00ms)

  5) test escape velocity of moon is correct (PhysicsTest)
     test/physics_test.exs:14
     ** (FunctionClauseError) no function clause matching in Converter.to_km/1

     The following arguments were given to Converter.to_km/1:

         # 1
         2375.1809330874535

     Attempted function clauses (showing 1 out of 1):

         def to_km(val) when -is_integer(val)-

     code: ev = Physics.Rocketry.escape_velocity(:moon)
     stacktrace:
       (physics) lib/converter.ex:27: Converter.to_km/1
       (physics) lib/physics/rocketry.ex:25: Physics.Rocketry.escape_velocity/1
       test/physics_test.exs:15: (test)

  * test escape velocity of mars is correct (0.00ms)

  6) test escape velocity of mars is correct (PhysicsTest)
     test/physics_test.exs:9
     ** (FunctionClauseError) no function clause matching in Converter.to_km/1

     The following arguments were given to Converter.to_km/1:

         # 1
         5007.130210128

     Attempted function clauses (showing 1 out of 1):

         def to_km(val) when -is_integer(val)-

     code: ev = Physics.Rocketry.escape_velocity(:mars)
     stacktrace:
       (physics) lib/converter.ex:27: Converter.to_km/1
       (physics) lib/physics/rocketry.ex:25: Physics.Rocketry.escape_velocity/1
       test/physics_test.exs:10: (test)

  * test Converting to to_light_seconds (0.00ms)


Finished in 0.06 seconds
8 tests, 6 failures

Randomized with seed 272000

I've made sure all my code matches the code here: https://github.com/bigmachine-io/taking-off/tree/7c05b129cd6c9bf7fd95a3aadecd0472eb510408. I'm assuming that this code should basically be the ending code for the Orbital Distance chapter.

Any help?

Mnesia chapter issues

I had 2 issues with amnesia_test.exs when completing this chapter:

1. Should be "Amnesia.start" instead of "Amnesia.Start"

• this only applies to the code shown in the video
• book & github code are correct

2. I needed to add a directive for "use Amnesia" in amnesia_test.exs or i get
   "(UndefinedFunctionError) function Amnesia.Helper.result/1 is undefined or private"

• seems to be missing from video, book & github code.
• think this is caused by a change to the Amnesia library (in Aug 2016).

confused by unit tests referenced in video around 45:32

The video says to look at chp 6 for more unit tests however when looking at that tag, the underlying Rocketry lib is completely different from what we've built so far on the video series and the tests all don't work....is that really the correct tag from which to pull at this point in the video?

Passing maps as function argument

Just started working through this book and it's been great so far!

A quick question on this example though --

  def to_light_seconds({:meters, meters} = val, precision: precision)  do
    (meters * 3.335638620368e-9) |> round_up
  end

What is val (in the functional argument) used for? When I run the tests, I get this warning:

warning: variable "val" is unused
  lib/physics/rocketry.ex:47

What is the point of val in this example? Also, is val bound to the map that is passed as argument?

Thanks!

Added Error Conditions - running the tests and watching the video don't correlate.

Hi. I checked out the code as explained in the video but running the tests does not correlate at all with what is shown in the video. The first error is multiple clauses of the same test being defined. The second, after commenting the second, is that no function clause because we are passing in a float. Am I doing something wrong or did the tests and the video get out of sync?
d2eb25f1789b9cd7c5e89973a84de1c45189c870 <--- this is the commit I checked out.

Additional error in compiler_problem_test.exs (@ Chapter 8)

in commit d2eb25f there is an error over and above the intentional errors discussed in the video.

There are 2 methods named as "test rounding an integer". As such the test resolution process does not follow the same flow as the video or the book. Instead a "ExUnit.DuplicateTestError" is thrown and no test assertions are shown (failing or otherwise).

Extra Credit Challenge

On the last page of the 'Calculating Orbital Distance' chapter, there's an 'Extra Credit Challenge'. We're supposed to fix the function and correctly apply the orbital term formula. I checked and double checked and can't see what's wrong. I'm sure it's a blatantly obvious thing, but can someone let me know what I'm missing?

Issue downloading Amnesia from GitHub (ch 13)

For chapter 13, when trying to use Amnesia, I get an error when downloading the package from Github.

For this line of deps() :

[{:timex, "~> 2.1.4"}, {:amnesia, github: "meh/amnesia", tag: :master}] 

I get the following error:

* Updating amnesia (https://github.com/meh/amnesia.git)
** (ArgumentError) all arguments for System.cmd/3 must be binaries
    (elixir) lib/system.ex:613: System.cmd/3
    (mix) lib/mix/scm/git.ex:250: Mix.SCM.Git.git!/2
    (mix) lib/mix/scm/git.ex:124: Mix.SCM.Git.checkout/2
    (elixir) lib/file.ex:1419: File.cd!/2
    (mix) lib/mix/dep/fetcher.ex:61: Mix.Dep.Fetcher.do_fetch/3
    (mix) lib/mix/dep/converger.ex:185: Mix.Dep.Converger.all/9
    (mix) lib/mix/dep/converger.ex:196: Mix.Dep.Converger.all/9
    (mix) lib/mix/dep/converger.ex:121: Mix.Dep.Converger.all/7

Although the video states not to download the package from Hex, I believe there has been updated version since the release of chapter 13. I am able to download the package fine with https://hex.pm/packages/amnesia/0.2.7, i.e.,

{:amnesia, "~> 0.2.7"}

I would like more editor setup information

Id like to know what all Elixir plugins you use with Sublime. Also Im curious what theme youre using with Sublime.

Physics.Repo not started

While going through the book I hit a roadblock on getting data back from the database. When I try to query something I get this error.

I am using the files from the BOMBS AWAY Commit and just adding a planet schema file and editing the following planet.ex file
planet.ex.txt

== Compilation error on file lib/physics/rocketry.ex ==
** (ArgumentError) repo Physics.Repo is not started, please ensure it is part of your supervision tree
    lib/ecto/query/planner.ex:65: Ecto.Query.Planner.query_lookup/5
    lib/ecto/query/planner.ex:48: Ecto.Query.Planner.query_with_cache/6
    lib/ecto/repo/queryable.ex:119: Ecto.Repo.Queryable.execute/5
    lib/ecto/repo/queryable.ex:40: Ecto.Repo.Queryable.all/4
    lib/planet.ex:21: Planet.select/0
    lib/physics/rocketry.ex:9: (module)

Concurrency Example Postgrex.close/1

I get error Postgrex.close/1 is undefined or private in the example where we are using the Postgrex driver directly. The Postgrex docs only show close/3 & close!/3 (although 1 of the parameters is optional so I think that also makes it close/2).

Named tuple in func signature? What is this?

{:inches, inches} = val

What is that doing? Is it a named tuple? You do not use val in the to_light_seconds function, so I'm not sure why it's there at all. And you can simply pass the result to round_up without having it be the name of val, so I just don't understand the point of it in the code. Yet, it's consistently in this entire chapter up until the very end.

def to_light_seconds({:inches, inches} = val)  do
    (inches * 8.472522095734715723e-11) |> round_up
end

def round_up(val) when is_float(val), do: trunc(val)