From 0eff2f77d0ae3dfb9def11a696afd338df993a54 Mon Sep 17 00:00:00 2001
From: Max VelDink <mveldink@justworks.com>
Date: Tue, 9 Jul 2024 13:20:18 -0400
Subject: [PATCH] feat: Add clearer message for CoercionNotSupportedError
 (#113)

---
 lib/typed/coercion.rb                                 |  6 +++---
 lib/typed/coercion/coercion_not_supported_error.rb    |  9 ++++++++-
 .../coercion/coercion_not_supported_error_test.rb     | 11 +++++++++++
 test/typed/coercion_test.rb                           |  2 +-
 4 files changed, 23 insertions(+), 5 deletions(-)
 create mode 100644 test/typed/coercion/coercion_not_supported_error_test.rb

diff --git a/lib/typed/coercion.rb b/lib/typed/coercion.rb
index b87be3f..18b37bd 100644
--- a/lib/typed/coercion.rb
+++ b/lib/typed/coercion.rb
@@ -11,11 +11,11 @@ def self.register_coercer(coercer)
 
     sig { type_parameters(:U).params(type: T::Types::Base, value: Value).returns(Result[Value, CoercionError]) }
     def self.coerce(type:, value:)
-      coercer = CoercerRegistry.instance.select_coercer_by(type: type)
+      coercer = CoercerRegistry.instance.select_coercer_by(type:)
 
-      return Failure.new(CoercionNotSupportedError.new) unless coercer
+      return Failure.new(CoercionNotSupportedError.new(type:)) unless coercer
 
-      coercer.new.coerce(type: type, value: value)
+      coercer.new.coerce(type:, value:)
     end
   end
 end
diff --git a/lib/typed/coercion/coercion_not_supported_error.rb b/lib/typed/coercion/coercion_not_supported_error.rb
index 4727e67..94d5e90 100644
--- a/lib/typed/coercion/coercion_not_supported_error.rb
+++ b/lib/typed/coercion/coercion_not_supported_error.rb
@@ -2,6 +2,13 @@
 
 module Typed
   module Coercion
-    class CoercionNotSupportedError < CoercionError; end
+    class CoercionNotSupportedError < CoercionError
+      extend T::Sig
+
+      sig { params(type: T::Types::Base).void }
+      def initialize(type:)
+        super("Coercer not found for type #{type}.")
+      end
+    end
   end
 end
diff --git a/test/typed/coercion/coercion_not_supported_error_test.rb b/test/typed/coercion/coercion_not_supported_error_test.rb
new file mode 100644
index 0000000..2a72b38
--- /dev/null
+++ b/test/typed/coercion/coercion_not_supported_error_test.rb
@@ -0,0 +1,11 @@
+# typed: true
+
+require "test_helper"
+
+class CoercionNotSupportedErrorTest < Minitest::Test
+  def test_formats_message
+    error = Typed::Coercion::CoercionNotSupportedError.new(type: T::Utils.coerce(RubyRank))
+
+    assert_equal("Coercer not found for type RubyRank.", error.message)
+  end
+end
diff --git a/test/typed/coercion_test.rb b/test/typed/coercion_test.rb
index ee2db17..2f79bad 100644
--- a/test/typed/coercion_test.rb
+++ b/test/typed/coercion_test.rb
@@ -24,6 +24,6 @@ def test_when_coercer_isnt_matched_coerce_returns_failure
     result = Typed::Coercion.coerce(type: T::Utils.coerce(BigDecimal), value: "testing")
 
     assert_failure(result)
-    assert_error(Typed::Coercion::CoercionNotSupportedError.new, result)
+    assert_error(Typed::Coercion::CoercionNotSupportedError.new(type: T::Utils.coerce(BigDecimal)), result)
   end
 end