leap

elixir/leap/.exercism/config.json

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+{
+  "authors": [
+    "rubysolo"
+  ],
+  "contributors": [
+    "angelikatyborska",
+    "Cohen-Carlisle",
+    "dalexj",
+    "devonestes",
+    "glennular",
+    "jinyeow",
+    "korbin",
+    "kytrinyx",
+    "lpil",
+    "neenjaw",
+    "parkerl",
+    "sotojuan",
+    "Teapane",
+    "waiting-for-dev"
+  ],
+  "files": {
+    "solution": [
+      "lib/year.ex"
+    ],
+    "test": [
+      "test/year_test.exs"
+    ],
+    "example": [
+      ".meta/example.ex"
+    ]
+  },
+  "blurb": "Given a year, report if it is a leap year.",
+  "source": "CodeRanch Cattle Drive, Assignment 3",
+  "source_url": "https://coderanch.com/t/718816/Leap"
+}

elixir/leap/.exercism/metadata.json

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+{"track":"elixir","exercise":"leap","id":"8bd50f0b5d7c4308bca361b49e63d755","url":"https://exercism.org/tracks/elixir/exercises/leap","handle":"negrienko","is_requester":true,"auto_approve":false}

elixir/leap/.formatter.exs

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+# Used by "mix format"
+[
+  inputs: ["{mix,.formatter}.exs", "{config,lib,test}/**/*.{ex,exs}"]
+]

elixir/leap/.gitignore

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+# The directory Mix will write compiled artifacts to.
+/_build/
+
+# If you run "mix test --cover", coverage assets end up here.
+/cover/
+
+# The directory Mix downloads your dependencies sources to.
+/deps/
+
+# Where third-party dependencies like ExDoc output generated docs.
+/doc/
+
+# Ignore .fetch files in case you like to edit your project deps locally.
+/.fetch
+
+# If the VM crashes, it generates a dump, let's ignore it too.
+erl_crash.dump
+
+# Also ignore archive artifacts (built via "mix archive.build").
+*.ez
+
+# Ignore package tarball (built via "mix hex.build").
+leap-*.tar
+

elixir/leap/HELP.md

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+# Help
+
+## Running the tests
+
+From the terminal, change to the base directory of the exercise then execute the tests with:
+
+```bash
+$ mix test
+```
+
+This will execute the test file found in the `test` subfolder -- a file ending in `_test.exs`
+
+Documentation:
+
+* [`mix test` - Elixir's test execution tool](https://hexdocs.pm/mix/Mix.Tasks.Test.html)
+* [`ExUnit` - Elixir's unit test library](https://hexdocs.pm/ex_unit/ExUnit.html)
+
+## Pending tests
+
+In test suites of practice exercises, all but the first test have been tagged to be skipped.
+
+Once you get a test passing, you can unskip the next one by commenting out the relevant `@tag :pending` with a `#` symbol.
+
+For example:
+
+```elixir
+# @tag :pending
+test "shouting" do
+  assert Bob.hey("WATCH OUT!") == "Whoa, chill out!"
+end
+```
+
+If you wish to run all tests at once, you can include all skipped test by using the `--include` flag on the `mix test` command:
+
+```bash
+$ mix test --include pending
+```
+
+Or, you can enable all the tests by commenting out the `ExUnit.configure` line in the file `test/test_helper.exs`.
+
+```elixir
+# ExUnit.configure(exclude: :pending, trace: true)
+```
+
+## Useful `mix test` options
+
+* `test/<FILE>.exs:LINENUM` - runs only a single test, the test from `<FILE>.exs` whose definition is on line `LINENUM`
+* `--failed` - runs only tests that failed the last time they ran
+* `--max-failures` - the suite stops evaluating tests when this number of test failures
+is reached
+* `--seed 0` - disables randomization so the tests in a single file will always be ran
+in the same order they were defined in
+
+## Submitting your solution
+
+You can submit your solution using the `exercism submit lib/year.ex` command.
+This command will upload your solution to the Exercism website and print the solution page's URL.
+
+It's possible to submit an incomplete solution which allows you to:
+
+- See how others have completed the exercise
+- Request help from a mentor
+
+## Need to get help?
+
+If you'd like help solving the exercise, check the following pages:
+
+- The [Elixir track's documentation](https://exercism.org/docs/tracks/elixir)
+- The [Elixir track's programming category on the forum](https://forum.exercism.org/c/programming/elixir)
+- [Exercism's programming category on the forum](https://forum.exercism.org/c/programming/5)
+- The [Frequently Asked Questions](https://exercism.org/docs/using/faqs)
+
+Should those resources not suffice, you could submit your (incomplete) solution to request mentoring.
+
+If you're stuck on something, it may help to look at some of the [available resources](https://exercism.org/docs/tracks/elixir/resources) out there where answers might be found.

elixir/leap/README.md

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+# Leap
+
+Welcome to Leap on Exercism's Elixir Track.
+If you need help running the tests or submitting your code, check out `HELP.md`.
+
+## Instructions
+
+Given a year, report if it is a leap year.
+
+The tricky thing here is that a leap year in the Gregorian calendar occurs:
+
+```text
+on every year that is evenly divisible by 4
+  except every year that is evenly divisible by 100
+    unless the year is also evenly divisible by 400
+```
+
+For example, 1997 is not a leap year, but 1996 is.
+1900 is not a leap year, but 2000 is.
+
+## Notes
+
+Though our exercise adopts some very simple rules, there is more to learn!
+
+For a delightful, four minute explanation of the whole leap year phenomenon, go watch [this youtube video][video].
+
+[video]: https://www.youtube.com/watch?v=xX96xng7sAE
+
+## Source
+
+### Created by
+
+- @rubysolo
+
+### Contributed to by
+
+- @angelikatyborska
+- @Cohen-Carlisle
+- @dalexj
+- @devonestes
+- @glennular
+- @jinyeow
+- @korbin
+- @kytrinyx
+- @lpil
+- @neenjaw
+- @parkerl
+- @sotojuan
+- @Teapane
+- @waiting-for-dev
+
+### Based on
+
+CodeRanch Cattle Drive, Assignment 3 - https://coderanch.com/t/718816/Leap

elixir/leap/lib/year.ex

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+defmodule Year do
+  @doc """
+  Returns whether 'year' is a leap year.
+
+  A leap year occurs:
+
+  on every year that is evenly divisible by 4
+    except every year that is evenly divisible by 100
+      unless the year is also evenly divisible by 400
+  """
+  @spec leap_year?(non_neg_integer) :: boolean
+  def leap_year?(year) when rem(year, 400) == 0, do: true
+  def leap_year?(year) when rem(year, 100) == 0, do: false
+  def leap_year?(year) when rem(year, 4) == 0, do: true
+  def leap_year?(_year), do: false
+end

elixir/leap/mix.exs

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+defmodule Year.MixProject do
+  use Mix.Project
+
+  def project do
+    [
+      app: :year,
+      version: "0.1.0",
+      # elixir: "~> 1.8",
+      start_permanent: Mix.env() == :prod,
+      deps: deps()
+    ]
+  end
+
+  # Run "mix help compile.app" to learn about applications.
+  def application do
+    [
+      extra_applications: [:logger]
+    ]
+  end
+
+  # Run "mix help deps" to learn about dependencies.
+  defp deps do
+    [
+      # {:dep_from_hexpm, "~> 0.3.0"},
+      # {:dep_from_git, git: "https://github.com/elixir-lang/my_dep.git", tag: "0.1.0"}
+    ]
+  end
+end

elixir/leap/test/test_helper.exs

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+ExUnit.start()
+ExUnit.configure(exclude: :pending, trace: true)

elixir/leap/test/year_test.exs

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+defmodule YearTest do
+  use ExUnit.Case
+
+  # @tag :pending
+  test "year not divisible by 4 is common year" do
+    refute Year.leap_year?(2015)
+  end
+
+  # @tag :pending
+  test "year divisible by 2, not divisible by 4 is common year" do
+    refute Year.leap_year?(1970)
+  end
+
+  # @tag :pending
+  test "year divisible by 4, not divisible by 100 is leap year" do
+    assert Year.leap_year?(1996)
+  end
+
+  # @tag :pending
+  test "year divisible by 4 and 5 is still a leap year" do
+    assert Year.leap_year?(1960)
+  end
+
+  @tag :pending
+  test "year divisible by 100, not divisible by 400 is common year" do
+    refute Year.leap_year?(2100)
+  end
+
+  # @tag :pending
+  test "year divisible by 100 but not by 3 is still not a leap year" do
+    refute Year.leap_year?(1900)
+  end
+
+  # @tag :pending
+  test "year divisible by 400 is leap year" do
+    assert Year.leap_year?(2000)
+  end
+
+  # @tag :pending
+  test "year divisible by 400 but not by 125 is still a leap year" do
+    assert Year.leap_year?(2400)
+  end
+
+  # @tag :pending
+  test "year divisible by 200, not divisible by 400 in common year" do
+    refute Year.leap_year?(1800)
+  end
+end