Add a normalization for better flexible in AstData file

Author: Premwoik

test/gradient/ast_specifier_test.exs

@@ -3,6 +3,7 @@ defmodule Gradient.AstSpecifierTest do
   doctest Gradient.AstSpecifier
 
   alias Gradient.AstSpecifier
+  alias Gradient.AstData
 
   import Gradient.TestHelpers
 
@@ -11,11 +12,14 @@ defmodule Gradient.AstSpecifierTest do
   end
 
   describe "specifying expression" do
-    for {name, args, expected} <- Gradient.AstData.ast_data() do
+    for {name, args, expected} <- AstData.ast_data() do
       test "#{name}" do
         {ast, tokens, opts} = unquote(Macro.escape(args))
-        expected = unquote(Macro.escape(expected))
-        assert expected == elem(AstSpecifier.mapper(ast, tokens, opts), 0)
+        expected = AstData.normalize_expression(unquote(Macro.escape(expected)))
+
+        actual = AstData.normalize_expression(elem(AstSpecifier.mapper(ast, tokens, opts), 0))
+
+        assert expected == actual
       end
     end
   end

test/support/ast_data.ex

@@ -1,4 +1,14 @@
 defmodule Gradient.AstData do
+  @moduledoc """
+  Stores the test cases data for expressions line specifying. To increase the flexibility
+  the data need normalization before equality assertion. Thus we check only the line change,
+  not the exact value and there is no need to update expected values when the file content
+  changes.
+
+  This way of testing is useful only for more complex expressions in which we can observe
+  some line change. For example, look at the pipe operator cases.
+  """
+
   require Gradient.Debug
   import Gradient.Debug, only: [elixir_to_ast: 1]
   import Gradient.TestHelpers
@@ -59,14 +69,6 @@ defmodule Gradient.AstData do
       [{:integer, 56, 1}, {:atom, 55, :ok}]}}
   end
 
-  defp example do
-    {__ENV__.function,
-     {__ENV__.line,
-      elixir_to_ast do
-        :ok
-      end, __ENV__.line}, _expected = {}}
-  end
-
   @spec ast_data() :: [
           {atom(), {Types.abstract_expr(), Types.tokens(), Types.options()}, tuple()}
         ]
@@ -77,4 +79,17 @@ defmodule Gradient.AstData do
       {name, {ast, tokens, [line: start_line, end_line: end_line]}, expected}
     end)
   end
+
+  def normalize_expression(expression) do
+    {expression, _} =
+      :erl_parse.mapfold_anno(
+        fn anno, acc ->
+          {{:erl_anno.line(anno) - acc, :erl_anno.column(anno)}, acc}
+        end,
+        :erl_anno.line(elem(expression, 1)),
+        expression
+      )
+
+    expression
+  end
 end