Initial implementation

MainShayne233 · Nov 13, 2019 · bce6ae0 · bce6ae0
1 parent 8b95275
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Showing 4 changed files with 129 additions and 19 deletions.
diff --git a/README.md b/README.md
@@ -2,7 +2,14 @@
 
 Test the Elixir code in your markdown!
 
-<!--- TESTME -->
+<!--- MARKDOWN_TEST_START -->
+```elixir
+iex> 1 + 2
+3
+```
+<!--- MARKDOWN_TEST_END -->
+
+<!--- MARKDOWN_TEST_START -->
 ```elixir
 defmodule MyModule do
   def add(x, y), do: x + y
@@ -13,7 +20,8 @@ iex> x = 1
 ...> MyModule.add(x, y)
 3
 
-iex> MyModule.add(x, y)
-3
+iex> MyModule.add(1, 2)
+4
 ```
+<!--- MARKDOWN_TEST_END -->
 
diff --git a/lib/markdown_test.ex b/lib/markdown_test.ex
@@ -1,18 +1,122 @@
 defmodule MarkdownTest do
-  @moduledoc """
-  Documentation for MarkdownTest.
-  """
+  defmodule TestBlock do
+    defstruct [:preface_code, cases: []]
+  end
+
+  @test_block_start "<!--- MARKDOWN_TEST_START -->"
+  @test_block_end "<!--- MARKDOWN_TEST_END -->"
+
+  @markdown_code_delimiter_pattern ~r/```(elixir)?/
+
+  defmacro __using__([]) do
+    quote do
+      import MarkdownTest, only: [test_markdown: 1]
+    end
+  end
+
+  defmacro test_markdown(path) do
+    file = fetch_file!(path)
+
+    test_blocks = parse_test_blocks!(file)
 
-  @doc """
-  Hello world.
+    describes =
+      test_blocks
+      |> Enum.with_index()
+      |> Enum.map(fn {test_block, index} ->
+        tests =
+          test_block.cases
+          |> Enum.with_index()
+          |> Enum.map(fn {{expression, expected}, index} ->
+            quote do
+              test "case: #{unquote(index)}" do
+                assert unquote(expression) === unquote(expected)
+              end
+            end
+          end)
 
-  ## Examples
+        quote do
+          describe "block #{unquote(index)}" do
+            unquote(test_block.preface_code)
+
+            unquote_splicing(tests)
+          end
+        end
+      end)
+
+    quote do
+      (unquote_splicing(describes))
+    end
+  end
+
+  defp parse_test_blocks!(file) do
+    file
+    |> parse_raw_code_blocks!()
+    |> Enum.map(&parse_code_block!/1)
+  end
+
+  defp parse_raw_code_blocks!(file) do
+    file
+    |> String.split(@test_block_start)
+    |> Enum.drop(1)
+    |> Enum.map(&(String.split(&1, @test_block_end) |> hd()))
+    |> Enum.map(&String.replace(&1, @markdown_code_delimiter_pattern, ""))
+  end
 
-      iex> MarkdownTest.hello()
-      :world
+  defp parse_code_block!(raw_code_block) do
+    preface_code = parse_preface_code!(raw_code_block)
+    test_cases = parse_test_cases!(raw_code_block)
 
-  """
-  def hello do
-    :world
+    %TestBlock{
+      preface_code: preface_code,
+      cases: test_cases
+    }
   end
+
+  defp parse_preface_code!(raw_code_block) do
+    raw_code_block
+    |> String.split("iex>")
+    |> hd()
+    |> String.trim()
+    |> Code.string_to_quoted!()
+  end
+
+  defp parse_test_cases!(raw_code_block) do
+    {raw_test_cases, _} =
+      raw_code_block
+      |> String.split("\n")
+      |> Enum.map(&String.trim/1)
+      |> Enum.reduce({[], :init}, fn
+        "iex> " <> expression_start, {cases, :init} ->
+          {[{expression_start, nil} | cases], :expression}
+
+        _, {cases, :init} ->
+          {cases, :init}
+
+        "...> " <> expression_chunk, {[{current_expression, nil} | cases], :expression} ->
+          {[{current_expression <> "\n" <> expression_chunk, nil} | cases], :expression}
+
+        expected_start, {[{current_expression, nil} | cases], :expression} ->
+          {[{current_expression, expected_start} | cases], :expected}
+
+        "" <> _, {cases, :expected} ->
+          {cases, :init}
+
+        expected_chunk, {[{current_expression, current_expected} | cases], :expected} ->
+          {[{current_expression, current_expected <> "\n" <> expected_chunk} | cases]}
+      end)
+
+    raw_test_cases
+    |> Enum.map(fn {raw_expression, raw_expected} ->
+      {Code.string_to_quoted!(raw_expression), Code.string_to_quoted!(raw_expected)}
+    end)
+    |> Enum.reverse()
+  end
+
+  defp fetch_file!(path) do
+    File.read(path)
+    |> unwrap_or_raise("No file at path: #{path}")
+  end
+
+  defp unwrap_or_raise({:ok, term}, _message), do: term
+  defp unwrap_or_raise(_, message), do: raise(%RuntimeError{message: message})
 end
diff --git a/mix.exs b/mix.exs
@@ -17,7 +17,7 @@ defmodule MarkdownTest.MixProject do
 
   defp deps do
     [
-      {:mix_test_watch, "~> 0.9.0", only: :dev, runtime: false},
+      {:mix_test_watch, "~> 0.9.0", only: :dev, runtime: false}
     ]
   end
 end
diff --git a/test/markdown_test_test.exs b/test/markdown_test_test.exs
@@ -1,8 +1,6 @@
 defmodule MarkdownTestTest do
   use ExUnit.Case
-  doctest MarkdownTest
+  use MarkdownTest
 
-  test "greets the world" do
-    assert MarkdownTest.hello() == :world
-  end
+  test_markdown("README.md")
 end