Add Naming/BlockParameterName rule

spec/ameba/rule/naming/block_parameter_name_spec.cr

@@ -0,0 +1,100 @@
+require "../../../spec_helper"
+
+module Ameba::Rule::Naming
+  subject = BlockParameterName.new
+    .tap(&.min_name_length = 3)
+    .tap(&.allowed_names = %w[_ e i j k v])
+
+  describe BlockParameterName do
+    it "passes if block parameter name matches #allowed_names" do
+      subject.allowed_names.each do |name|
+        expect_no_issues subject, <<-CRYSTAL
+          %w[].each { |#{name}| }
+          CRYSTAL
+      end
+    end
+
+    it "fails if block parameter name doesn't match #allowed_names" do
+      expect_issue subject, <<-CRYSTAL
+        %w[].each { |x| }
+                   # ^ error: Disallowed block parameter name found
+        CRYSTAL
+    end
+
+    context "properties" do
+      context "#min_name_length" do
+        it "allows setting custom values" do
+          rule = BlockParameterName.new
+          rule.allowed_names = %w[a b c]
+
+          rule.min_name_length = 3
+          expect_issue rule, <<-CRYSTAL
+            %w[].each { |x| }
+                       # ^ error: Disallowed block parameter name found
+            CRYSTAL
+
+          rule.min_name_length = 1
+          expect_no_issues rule, <<-CRYSTAL
+            %w[].each { |x| }
+            CRYSTAL
+        end
+      end
+
+      context "#allow_names_ending_in_numbers" do
+        it "allows setting custom values" do
+          rule = BlockParameterName.new
+          rule.min_name_length = 1
+          rule.allowed_names = %w[]
+
+          rule.allow_names_ending_in_numbers = false
+          expect_issue rule, <<-CRYSTAL
+            %w[].each { |x1| }
+                       # ^ error: Disallowed block parameter name found
+            CRYSTAL
+
+          rule.allow_names_ending_in_numbers = true
+          expect_no_issues rule, <<-CRYSTAL
+            %w[].each { |x1| }
+            CRYSTAL
+        end
+      end
+
+      context "#allowed_names" do
+        it "allows setting custom names" do
+          rule = BlockParameterName.new
+          rule.min_name_length = 3
+
+          rule.allowed_names = %w[a b c]
+          expect_issue rule, <<-CRYSTAL
+            %w[].each { |x| }
+                       # ^ error: Disallowed block parameter name found
+            CRYSTAL
+
+          rule.allowed_names = %w[x y z]
+          expect_no_issues rule, <<-CRYSTAL
+            %w[].each { |x| }
+            CRYSTAL
+        end
+      end
+
+      context "#forbidden_names" do
+        it "allows setting custom names" do
+          rule = BlockParameterName.new
+          rule.min_name_length = 1
+          rule.allowed_names = %w[]
+
+          rule.forbidden_names = %w[x y z]
+          expect_issue rule, <<-CRYSTAL
+            %w[].each { |x| }
+                       # ^ error: Disallowed block parameter name found
+            CRYSTAL
+
+          rule.forbidden_names = %w[a b c]
+          expect_no_issues rule, <<-CRYSTAL
+            %w[].each { |x| }
+            CRYSTAL
+        end
+      end
+    end
+  end
+end