Use correct line length for results (#8)

* Use correct line length for results

* Update changelog

* Fix compilation warning

CHANGELOG.md

@@ -5,6 +5,7 @@
 - Support parsing multiline doctests with `iex>` on all lines, but reformat them using `...>` on every line but the first one.
 - Fix implementation for multiline results. Multiline results are allowed, and they can be terminated with an empty new line or another doctest.
 - Support exception expressions (`** (ModuleName) message`) in results.
+- Desired line length for doctest result now accounts for its indentation.
 
 ## 0.1.0 (2024-02-25)
 

lib/doctest_formatter/formatter.ex

@@ -70,6 +70,10 @@ defmodule DoctestFormatter.Formatter do
   end
 
   def do_format_expression(%DoctestExpression{} = chunk, opts) do
+    format_lines(chunk, opts) ++ format_result(chunk, opts)
+  end
+
+  defp format_lines(chunk, opts) do
     first_line_symbol = "iex> "
     next_line_symbol = "...> "
 
@@ -78,17 +82,25 @@ defmodule DoctestFormatter.Formatter do
     line_length =
       desired_line_length - elem(chunk.indentation, 1) - String.length(first_line_symbol)
 
-    formatted_lines =
-      chunk.lines
-      |> Enum.join("\n")
-      |> Code.format_string!(Keyword.put(opts, :line_length, line_length))
-      |> IO.iodata_to_binary()
-      |> String.split("\n")
-      |> Enum.with_index()
-      |> Enum.map(fn {line, index} ->
-        symbol = if(index == 0, do: first_line_symbol, else: next_line_symbol)
-        Indentation.indent(symbol <> line, chunk.indentation)
-      end)
+    opts = Keyword.put(opts, :line_length, line_length)
+
+    chunk.lines
+    |> Enum.join("\n")
+    |> Code.format_string!(opts)
+    |> IO.iodata_to_binary()
+    |> String.split("\n")
+    |> Enum.with_index()
+    |> Enum.map(fn {line, index} ->
+      symbol = if(index == 0, do: first_line_symbol, else: next_line_symbol)
+      Indentation.indent(symbol <> line, chunk.indentation)
+    end)
+  end
+
+  defp format_result(chunk, opts) do
+    desired_line_length = Keyword.get(opts, :line_length, default_elixir_line_length())
+
+    line_length = desired_line_length - elem(chunk.indentation, 1)
+    opts = Keyword.put(opts, :line_length, line_length)
 
     string_result =
       chunk.result
@@ -104,14 +116,11 @@ defmodule DoctestFormatter.Formatter do
         |> IO.iodata_to_binary()
       end
 
-    formatted_result =
-      string_result
-      |> String.split("\n")
-      |> Enum.map(fn line ->
-        Indentation.indent(line, chunk.indentation)
-      end)
-
-    formatted_lines ++ formatted_result
+    string_result
+    |> String.split("\n")
+    |> Enum.map(fn line ->
+      Indentation.indent(line, chunk.indentation)
+    end)
   end
 
   defp exception_result?(string) do

test/doctest_formatter/formatter_test.exs

@@ -649,7 +649,7 @@ defmodule DoctestFormatter.FormatterTest do
       assert output == desired_output
     end
 
-    test "adjust desired line length to fit the indentation and 'iex> '" do
+    test "adjust desired test code line length to fit the indentation and 'iex> '" do
       opts = [line_length: 30]
 
       input =
@@ -677,6 +677,34 @@ defmodule DoctestFormatter.FormatterTest do
       assert output == desired_output
     end
 
+    test "adjust desired result line length to fit the indentation" do
+      opts = [line_length: 30]
+
+      input =
+        """
+        defmodule Foo do
+          @doc \"""
+                        iex> "aaa"
+                        "a" <> "a" <> "a"
+          \"""
+        end
+        """
+
+      desired_output =
+        """
+        defmodule Foo do
+          @doc \"""
+                        iex> "aaa"
+                        "a" <>
+                          "a" <> "a"
+          \"""
+        end
+        """
+
+      output = format(input, opts)
+      assert output == desired_output
+    end
+
     test "can handle exceptions in results" do
       input =
         """