Add 'found atom/string key, expected string/atom' mismatch detection …

…to literal map matcher Fixes #40
mtrudel · Nov 12, 2024 · 93470d7 · 93470d7
1 parent 3a87dc5
commit 93470d7
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Showing 2 changed files with 33 additions and 5 deletions.
diff --git a/lib/machete/matchers/literal_map_matcher.ex b/lib/machete/matchers/literal_map_matcher.ex
@@ -21,15 +21,35 @@ defmodule Machete.LiteralMapMatcher do
       a_keys = a |> Map.keys() |> MapSet.new()
       b_keys = b |> Map.keys() |> MapSet.new()
 
+      extra_keys = MapSet.difference(b_keys, a_keys)
+      missing_keys = MapSet.difference(a_keys, b_keys)
+
+      atom_keys =
+        extra_keys
+        |> Enum.filter(&(is_atom(&1) && MapSet.member?(missing_keys, to_string(&1))))
+        |> MapSet.new()
+
+      string_keys =
+        extra_keys
+        |> Enum.filter(
+          &(is_binary(&1) && MapSet.member?(missing_keys, String.to_existing_atom(&1)))
+        )
+        |> MapSet.new()
+
       extra_keys =
-        MapSet.difference(b_keys, a_keys)
-        |> Enum.flat_map(&mismatch("Unexpected key", &1))
+        extra_keys
+        |> MapSet.difference(atom_keys)
+        |> MapSet.difference(string_keys)
 
       missing_keys =
-        MapSet.difference(a_keys, b_keys)
-        |> Enum.flat_map(&mismatch("Missing key", &1))
+        missing_keys
+        |> MapSet.difference(atom_keys |> Enum.map(&Kernel.to_string/1) |> MapSet.new())
+        |> MapSet.difference(string_keys |> Enum.map(&String.to_existing_atom/1) |> MapSet.new())
 
-      extra_keys ++ missing_keys
+      Enum.flat_map(extra_keys, &mismatch("Unexpected key", &1)) ++
+        Enum.flat_map(missing_keys, &mismatch("Missing key", &1)) ++
+        Enum.flat_map(atom_keys, &mismatch("Found atom key, expected string", &1)) ++
+        Enum.flat_map(string_keys, &mismatch("Found string key, expected atom", &1))
     end
 
     defp mismatched_values(a, b) do

diff --git a/test/machete/matchers/literal_map_matcher_test.exs b/test/machete/matchers/literal_map_matcher_test.exs
@@ -21,6 +21,14 @@ defmodule LiteralMapMatcherTest do
     assert %{a: 1} ~>> %{} ~> mismatch("Unexpected key", :a)
   end
 
+  test "produces a useful mismatch on atom entries where strings were expected" do
+    assert %{a: 1} ~>> %{"a" => 1} ~> mismatch("Found atom key, expected string", :a)
+  end
+
+  test "produces a useful mismatch on atom entries where atoms were expected" do
+    assert %{"a" => 1} ~>> %{a: 1} ~> mismatch("Found string key, expected atom", "a")
+  end
+
   test "produces a useful mismatch on non-maps" do
     assert 1 ~>> %{} ~> mismatch("Value is not a map")
   end