Mark methods used in Minitest predicates as alive

Signed-off-by: Alexandre Terrasa <[email protected]>

lib/spoom/deadcode/plugins/minitest.rb

@@ -30,6 +30,16 @@ def on_define_method(definition)
 
           @index.ignore(definition) if ignored_subclass?(owner)
         end
+
+        sig { override.params(send: Send).void }
+        def on_send(send)
+          case send.name
+          when "assert_predicate", "refute_predicate"
+            name = send.args[1]&.slice
+            return unless name
+
+            @index.reference_method(name.delete_prefix(":"), send.location)
+          end
         end
       end
     end

test/spoom/deadcode/plugins/minitest_test.rb

@@ -84,6 +84,26 @@ def some_other_test; end
           refute_ignored(index, "some_other_test")
         end
 
+        def test_ignore_minitest_predicates
+          @project.write!("test/foo_test.rb", <<~RB)
+            class FooTest
+              def alive1; end
+              def alive2; end
+              def dead; end
+
+              def test_something
+                assert_predicate(foo, :alive1)
+                refute_predicate(foo, :alive2)
+              end
+            end
+          RB
+
+          index = index_with_plugins
+          assert_alive(index, "alive1")
+          assert_alive(index, "alive2")
+          assert_dead(index, "dead")
+        end
+
         private
 
         sig { returns(Deadcode::Index) }