1 files changed, 60 insertions, 0 deletions
diff --git a/test/prism/attribute_write_test.rb b/test/prism/attribute_write_test.rb
new file mode 100644
index 0000000000..bd83d72da3
--- /dev/null
+++ b/test/prism/attribute_write_test.rb
@@ -0,0 +1,60 @@
+# frozen_string_literal: true
+
+require_relative "test_helper"
+
+module Prism
+  class AttributeWriteTest < TestCase
+    module Target
+      def self.value
+        2
+      end
+
+      def self.value=(value)
+        2
+      end
+
+      def self.[]=(index, value)
+        2
+      end
+    end
+
+    def test_named_call_with_operator
+      assert_attribute_write("Target.value = 1")
+    end
+
+    def test_named_call_without_operator
+      assert_attribute_write("Target.value=(1)")
+    end
+
+    def test_indexed_call_with_operator
+      assert_attribute_write("Target[0] = 1")
+    end
+
+    def test_indexed_call_without_operator
+      refute_attribute_write("Target.[]=(0, 1)")
+    end
+
+    def test_comparison_operators
+      refute_attribute_write("Target.value == 1")
+      refute_attribute_write("Target.value === 1")
+    end
+
+    private
+
+    def parse(source)
+      Prism.parse(source).value.statements.body.first
+    end
+
+    def assert_attribute_write(source)
+      call = parse(source)
+      assert(call.attribute_write?)
+      assert_equal(1, eval(source))
+    end
+
+    def refute_attribute_write(source)
+      call = parse(source)
+      refute(call.attribute_write?)
+      refute_equal(1, eval(source))
+    end
+  end
+end