Add FizzBadd implementation

lib/fizz_badd.ex

@@ -2,4 +2,56 @@ defmodule FizzBadd do
   @moduledoc """
   Documentation for FizzBadd.
   """
+
+  alias __MODULE__.ShittyFizzBuzz, as: ShittyFizzBuzz
+  alias __MODULE__.StatementWrapper, as: StatementWrapper
+
+  def generate(n) when not is_integer(n) do
+    raise ArgumentError, "expects Integer, not `#{n}`"
+  end
+  def generate(n) when n < 1 do
+    raise ArgumentError, "can't generate negative lines (#{n})"
+  end
+  def generate(n) do """
+    defmodule FizzBuzz do
+    #{moduledoc()}
+    #{integer_guard()}
+    #{positive_guard()}
+    #{in_range_guard(n)}
+      def fizz_buzz(n) do
+    #{statements(n)}
+      end
+    end
+    """
+  end
+
+  defp moduledoc, do: """
+    @moduledoc \"""
+    A Fizz Buzz implementation.
+    \"""
+  """
+
+  defp integer_guard, do: """
+    def fizz_buzz(n) when not is_integer(n) do
+      raise ArgumentError, "expects Integer, not `\#{n}`"
+    end
+  """
+
+  defp positive_guard, do: """
+    def fizz_buzz(n) when n < 1 do
+      raise ArgumentError, "can't Fizz Buzz negative numbers (\#{n})"
+    end
+  """
+
+  defp in_range_guard(n), do: """
+    def fizz_buzz(n) when n > #{n} do
+      raise ArgumentError, "Fizz Buzz not implemented beyond #{n} (\#{n})"
+    end
+  """
+
+  def statements(n) do
+    n
+    |> ShittyFizzBuzz.statements
+    |> StatementWrapper.wrap(indent: "    ")
+  end
 end

test/fizz_badd_test.exs

@@ -1,4 +1,103 @@
 defmodule FizzBaddTest do
   use ExUnit.Case, async: true
   doctest FizzBadd
+
+  test "won't generate empty implementations" do
+    assert_raise ArgumentError, fn ->
+      FizzBadd.generate(0)
+    end
+  end
+
+  test "won't accept arguments out of range" do
+    assert_raise ArgumentError, fn ->
+      FizzBadd.generate(-1)
+    end
+  end
+
+  test "generates the correct implementation given 1" do
+    assert FizzBadd.generate(1) == """
+    defmodule FizzBuzz do
+      @moduledoc \"""
+      A Fizz Buzz implementation.
+      \"""
+
+      def fizz_buzz(n) when not is_integer(n) do
+        raise ArgumentError, "expects Integer, not `\#{n}`"
+      end
+
+      def fizz_buzz(n) when n < 1 do
+        raise ArgumentError, "can't Fizz Buzz negative numbers (\#{n})"
+      end
+
+      def fizz_buzz(n) when n > 1 do
+        raise ArgumentError, "Fizz Buzz not implemented beyond 1 (\#{n})"
+      end
+
+      def fizz_buzz(n) do
+        if n == 1, do: IO.puts "1"
+      end
+    end
+    """
+  end
+
+  test "generates the correct implementation given 2" do
+    assert FizzBadd.generate(2) === """
+    defmodule FizzBuzz do
+      @moduledoc \"""
+      A Fizz Buzz implementation.
+      \"""
+
+      def fizz_buzz(n) when not is_integer(n) do
+        raise ArgumentError, "expects Integer, not `\#{n}`"
+      end
+
+      def fizz_buzz(n) when n < 1 do
+        raise ArgumentError, "can't Fizz Buzz negative numbers (\#{n})"
+      end
+
+      def fizz_buzz(n) when n > 2 do
+        raise ArgumentError, "Fizz Buzz not implemented beyond 2 (\#{n})"
+      end
+
+      def fizz_buzz(n) do
+        if n >= 1, do: IO.write "1"; if n > 1, do: IO.write ", "; if n == 2, do: IO.puts "2"
+      end
+    end
+    """
+  end
+
+  test "generates the correct implementation given 15" do
+    assert FizzBadd.generate(15) === """
+    defmodule FizzBuzz do
+      @moduledoc \"""
+      A Fizz Buzz implementation.
+      \"""
+
+      def fizz_buzz(n) when not is_integer(n) do
+        raise ArgumentError, "expects Integer, not `\#{n}`"
+      end
+
+      def fizz_buzz(n) when n < 1 do
+        raise ArgumentError, "can't Fizz Buzz negative numbers (\#{n})"
+      end
+
+      def fizz_buzz(n) when n > 15 do
+        raise ArgumentError, "Fizz Buzz not implemented beyond 15 (\#{n})"
+      end
+
+      def fizz_buzz(n) do
+        if n >= 1, do: IO.write "1"; if n > 1, do: IO.write ", "; if n >= 2, do: IO.write "2"; if n > 2, do: IO.write ", "
+        if n >= 3, do: IO.write "Fizz"; if n > 3, do: IO.write ", "; if n >= 4, do: IO.write "4"
+        if n > 4, do: IO.write ", "; if n >= 5, do: IO.write "Buzz"; if n > 5, do: IO.write ", "
+        if n >= 6, do: IO.write "Fizz"; if n > 6, do: IO.write ", "; if n >= 7, do: IO.write "7"
+        if n > 7, do: IO.write ", "; if n >= 8, do: IO.write "8"; if n > 8, do: IO.write ", "
+        if n >= 9, do: IO.write "Fizz"; if n > 9, do: IO.write ", "; if n >= 10, do: IO.write "Buzz"
+        if n > 10, do: IO.write ", "; if n >= 11, do: IO.write "11"; if n > 11, do: IO.write ", "
+        if n >= 12, do: IO.write "Fizz"; if n > 12, do: IO.write ", "; if n >= 13, do: IO.write "13"
+        if n > 13, do: IO.write ", "; if n >= 14, do: IO.write "14"; if n > 14, do: IO.write ", "
+        if n == 15, do: IO.puts "Fizz Buzz"
+      end
+    end
+    """
+  end
 end