match better in changer

lib/ex_factor/changer.ex

@@ -67,7 +67,7 @@ defmodule ExFactor.Changer do
   end
 
   defp find_alias_as(list, module) do
-    aalias = Enum.find(list, "", fn el -> el =~ "alias #{Util.module_to_string(module)}" end)
+    aalias = Enum.find(list, "", fn el -> match_alias?(el, module) end)
 
     if String.match?(aalias, ~r/, as: /) do
       aalias
@@ -134,12 +134,13 @@ defmodule ExFactor.Changer do
     target_module = Keyword.fetch!(opts, :target_module)
     target_string = Util.module_to_string(target_module)
 
-    if Enum.find(contents_list, fn el -> el =~ "alias #{target_string}" end) do
+    if Enum.find(contents_list, fn el -> match_alias?(el, target_string) end) do
       {state, contents_list}
     else
       contents_list
       |> Enum.reduce([], fn elem, acc ->
-        if elem =~ "alias #{source_string}" do
+        if match_alias?(elem, source_string) do
+        # if String.match?(elem, ~r/alias #{source_string}(\s|$|\,)/) do
           new_alias = String.replace(elem, source_string, target_string)
           [new_alias | [elem | acc]]
         else
@@ -150,4 +151,8 @@ defmodule ExFactor.Changer do
       |> then(fn list -> {state, list} end)
     end
   end
+
+  defp match_alias?(string, module_string) do
+    String.match?(string, ~r/alias #{module_string}(\s|$|\,)/)
+  end
 end

test/ex_factor/changer_test.exs

@@ -30,9 +30,11 @@ defmodule ExFactor.ChangerTest do
       content = """
       defmodule ExFactor.Tmp.CallerModule do
         alias ExFactor.Tmp.SourceMod
+        alias ExFactor.Tmp.SourceMod.Other
         def pub1(arg_a) do
           SourceMod.refactor1(arg_a)
         end
+        def pub2(), do: Other
       end
       """
 
@@ -49,9 +51,14 @@ defmodule ExFactor.ChangerTest do
 
       caller = File.read!("lib/ex_factor/tmp/caller_module.ex")
       assert caller =~ "alias ExFactor.Tmp.TargetModule"
+      # ensure we don't match dumbly
+      assert caller =~ "alias ExFactor.Tmp.SourceMod.Other"
+      refute caller =~ "alias ExFactor.Tmp.TargetModule.Other"
       assert caller =~ "TargetModule.refactor1(arg_a)"
     end
 
+    # update the annoying alias style: alias Foo.{Bar, Baz, Biz}
+
     test "only add alias entry if it's missing" do
       content = """
       defmodule ExFactor.Tmp.SourceMod do