Improve Assertitions by adding source line

Author: rrrene

lib/credo/test/assertions.ex

@@ -15,7 +15,7 @@ defmodule Credo.Test.Assertions do
 
   def refute_issues(issues) do
     assert [] == issues,
-           "There should be no issues, got #{Enum.count(issues)}: #{to_inspected(issues)}"
+           "There should be no issues, got #{Enum.count(issues)}:\n\n#{to_inspected(issues)}"
 
     issues
   end
@@ -24,7 +24,7 @@ defmodule Credo.Test.Assertions do
     refute Enum.empty?(issues), "There should be one issue, got none."
 
     assert Enum.count(issues) == 1,
-           "There should be only 1 issue, got #{Enum.count(issues)}: #{to_inspected(issues)}"
+           "There should be only 1 issue, got #{Enum.count(issues)}:\n\n#{to_inspected(issues)}"
 
     if callback do
       issues |> List.first() |> callback.()
@@ -37,17 +37,32 @@ defmodule Credo.Test.Assertions do
     assert Enum.count(issues) > 0, "There should be multiple issues, got none."
 
     assert Enum.count(issues) > 1,
-           "There should be more than one issue, got: #{to_inspected(issues)}"
+           "There should be more than one issue, got:\n\n#{to_inspected(issues)}"
 
     if callback, do: callback.(issues)
 
     issues
   end
 
-  def to_inspected(value) do
-    value
-    |> Inspect.Algebra.to_doc(%Inspect.Opts{})
-    |> Inspect.Algebra.format(50)
-    |> Enum.join("")
+  def to_inspected(value) when is_list(value) do
+    value |> Enum.map(&to_inspected/1) |> Enum.join("\n")
+  end
+
+  def to_inspected(%Credo.Issue{} = issue) do
+    inspected =
+      issue
+      |> Inspect.Algebra.to_doc(%Inspect.Opts{})
+      |> Inspect.Algebra.format(50)
+      |> Enum.join("")
+
+    if Credo.Test.Case.test_source_files?() do
+      """
+      #{inspected}
+
+      #{Credo.Test.Case.get_issue_inline(issue)}
+      """
+    else
+      inspected
+    end
   end
 end

lib/credo/test/case.ex

@@ -204,6 +204,7 @@ defmodule Credo.Test.Case do
       |> run_check(MyProject.MyCheck, foo_parameter: "bar")
   """
   def run_check(source_files, check, params \\ []) do
+    Process.put(:credo_test_source_files, source_files)
     issues = CheckRunner.run_check(source_files, check, params)
 
     check_on_malformed_issues(source_files, issues)
@@ -247,18 +248,54 @@ defmodule Credo.Test.Case do
         found trigger is not the given trigger:
           actual:   #{inspect(actual_trigger, pretty: true)}
           expected: #{inspect(trigger, pretty: true)}
+
+        #{get_issue_inline(issue)}
         """)
       end
     end
   end
 
-  defp get_source_line(source_files, %Credo.Issue{} = issue) do
+  @doc false
+  def test_source_files? do
+    test_source_files() != []
+  end
+
+  @doc false
+  def test_source_files do
+    Process.get(:credo_test_source_files, [])
+  end
+
+  @doc false
+  def get_issue_inline(issue) do
+    source_files = test_source_files()
+    source_line = get_source_line(source_files, issue)
+
+    marker =
+      if issue.column && issue.trigger != Credo.Issue.no_trigger() do
+        String.duplicate(" ", issue.column - 1) <>
+          String.duplicate("^", String.length(to_string(issue.trigger)))
+      else
+        ""
+      end
+
+    """
+    #{source_line}
+    #{marker}
+    """
+  end
+
+  defp get_source_line(source_files, %Credo.Issue{} = issue) when is_list(source_files) do
     source_files
     |> find_source_file(issue)
     |> Credo.SourceFile.line_at(issue.line_no)
   end
 
-  defp find_source_file(source_files, %Credo.Issue{filename: filename}) do
+  defp get_source_line(%Credo.SourceFile{} = source_file, %Credo.Issue{} = issue) do
+    Credo.SourceFile.line_at(source_file, issue.line_no)
+  end
+
+  defp find_source_file(source_files, %Credo.Issue{filename: filename})
+       when is_list(source_files) do
     Enum.find(source_files, &(&1.filename == filename)) || raise "Could not find source file"
   end