Add Naming/RescuedExceptionsVariableName rule

spec/ameba/rule/naming/rescued_exceptions_variable_name_spec.cr

@@ -0,0 +1,53 @@
+require "../../../spec_helper"
+
+module Ameba::Rule::Naming
+  subject = RescuedExceptionsVariableName.new
+
+  describe RescuedExceptionsVariableName do
+    it "passes if exception handler variable name matches #allowed_names" do
+      subject.allowed_names.each do |name|
+        expect_no_issues subject, <<-CRYSTAL
+          def foo
+            raise "foo"
+          rescue #{name}
+            nil
+          end
+          CRYSTAL
+      end
+    end
+
+    it "fails if exception handler variable name doesn't match #allowed_names" do
+      expect_issue subject, <<-CRYSTAL
+        def foo
+          raise "foo"
+        rescue wtf
+        # ^^^^^^^^ error: Disallowed variable name, use one of these instead: 'e', 'ex', 'exception'
+          nil
+        end
+        CRYSTAL
+    end
+
+    context "properties" do
+      context "#allowed_names" do
+        it "returns sensible defaults" do
+          rule = RescuedExceptionsVariableName.new
+          rule.allowed_names.should eq %w[e ex exception]
+        end
+
+        it "allows setting custom names" do
+          rule = RescuedExceptionsVariableName.new
+          rule.allowed_names = %w[foo]
+
+          expect_issue rule, <<-CRYSTAL
+            def foo
+              raise "foo"
+            rescue e
+            # ^^^^^^ error: Disallowed variable name, use 'foo' instead
+              nil
+            end
+            CRYSTAL
+        end
+      end
+    end
+  end
+end