Ameba::Rule -> Ameba::Rule::Base

spec/ameba/rule/base_spec.cr

@@ -0,0 +1,26 @@
+require "../../spec/spec_helper"
+
+module Ameba
+  describe Rule::Base do
+    describe "#catch" do
+      it "accepts and returns source" do
+        s = Source.new "", ""
+        DummyRule.new.catch(s).should eq s
+      end
+    end
+
+    describe "#name" do
+      it "returns name of the rule" do
+        DummyRule.new.name.should eq "Ameba::DummyRule"
+      end
+    end
+  end
+
+  describe Rule do
+    describe ".rules" do
+      it "returns a list of all defined rules" do
+        Rule.rules.includes?(DummyRule).should be_true
+      end
+    end
+  end
+end

spec/ameba/rule/comparison_to_boolean_spec.cr

@@ -0,0 +1,113 @@
+require "../../spec_helper"
+
+module Ameba::Rule
+  subject = ComparisonToBoolean.new
+
+  describe ComparisonToBoolean do
+    it "passes if there is no comparison to boolean" do
+      source = Source.new %(
+        a = true
+
+        if a
+          :ok
+        end
+
+        if true
+          :ok
+        end
+
+        unless s.empty?
+          :ok
+        end
+
+        :ok if a
+
+        :ok if a != 1
+
+        :ok if a == "true"
+
+        case a
+        when true
+          :ok
+        when false
+          :not_ok
+        end
+      )
+      subject.catch(source).should be_valid
+    end
+
+    context "boolean on the right" do
+      it "fails if there is == comparison to boolean" do
+        source = Source.new %(
+          if s.empty? == true
+            :ok
+          end
+        )
+        subject.catch(source).should_not be_valid
+      end
+
+      it "fails if there is != comparison to boolean" do
+        source = Source.new %(
+          if a != false
+            :ok
+          end
+        )
+        subject.catch(source).should_not be_valid
+      end
+
+      it "fails if there is case comparison to boolean" do
+        source = Source.new %(
+          a === true
+        )
+        subject.catch(source).should_not be_valid
+      end
+
+      it "reports rule, pos and message" do
+        source = Source.new "a != true", "source.cr"
+        subject.catch(source)
+
+        error = source.errors.first
+        error.rule.should_not be_nil
+        error.location.to_s.should eq "source.cr:1:1"
+        error.message.should eq "Comparison to a boolean is pointless"
+      end
+    end
+
+    context "boolean on the left" do
+      it "fails if there is == comparison to boolean" do
+        source = Source.new %(
+          if true == s.empty?
+            :ok
+          end
+        )
+        subject.catch(source).should_not be_valid
+      end
+
+      it "fails if there is != comparison to boolean" do
+        source = Source.new %(
+          if false != a
+            :ok
+          end
+        )
+        subject.catch(source).should_not be_valid
+      end
+
+      it "fails if there is case comparison to boolean" do
+        source = Source.new %(
+          true === a
+        )
+        subject.catch(source).should_not be_valid
+      end
+
+      it "reports rule, pos and message" do
+        source = Source.new "true != a", "source.cr"
+        subject.catch(source).should_not be_valid
+
+        error = source.errors.first
+        error.rule.should_not be_nil
+        error.location.to_s.should eq "source.cr:1:1"
+        error.message.should eq "Comparison to a boolean is pointless"
+      end
+    end
+  end
+end

spec/ameba/rule/constant_names_spec.cr

@@ -0,0 +1,51 @@
+require "../../spec_helper"
+
+module Ameba
+  subject = Rule::ConstantNames.new
+
+  private def it_reports_constant(code, expected)
+    it "reports constant name #{expected}" do
+      s = Source.new code
+      Rule::ConstantNames.new.catch(s).should_not be_valid
+      s.errors.first.message.should contain expected
+    end
+  end
+
+  describe Rule::ConstantNames do
+    it "passes if type names are screaming-cased" do
+      s = Source.new %(
+        LUCKY_NUMBERS     = [3, 7, 11]
+        DOCUMENTATION_URL = "http://crystal-lang.org/docs"
+
+        Int32
+
+        s : String = "str"
+
+        def works(n : Int32)
+        end
+
+        a = 1
+        myVar = 2
+        m_var = 3
+      )
+      subject.catch(s).should be_valid
+    end
+
+    it_reports_constant "MyBadConstant=1", "MYBADCONSTANT"
+    it_reports_constant "Wrong_NAME=2", "WRONG_NAME"
+    it_reports_constant "Wrong_Name=3", "WRONG_NAME"
+
+    it "reports rule, pos and message" do
+      s = Source.new %(
+        Const = 1
+      ), "source.cr"
+      subject.catch(s).should_not be_valid
+      error = s.errors.first
+      error.rule.should_not be_nil
+      error.location.to_s.should eq "source.cr:2:9"
+      error.message.should eq(
+        "Constant name should be screaming-cased: CONST, not Const"
+      )
+    end
+  end
+end

spec/ameba/rule/debugger_statement_spec.cr

@@ -0,0 +1,44 @@
+require "../../spec_helper"
+
+module Ameba::Rule
+  subject = DebuggerStatement.new
+
+  describe DebuggerStatement do
+    it "passes if there is no debugger statement" do
+      s = Source.new %(
+        "this is not a debugger statement"
+        s = "debugger"
+
+        def debugger(program)
+        end
+        debugger ""
+
+        class A
+          def debugger
+          end
+        end
+        A.new.debugger
+      )
+      subject.catch(s).should be_valid
+    end
+
+    it "fails if there is a debugger statement" do
+      s = Source.new %(
+        a = 2
+        debugger
+        a = a + 1
+      )
+      subject.catch(s).should_not be_valid
+    end
+
+    it "reports rule, pos and message" do
+      s = Source.new "debugger", "source.cr"
+      subject.catch(s).should_not be_valid
+
+      error = s.errors.first
+      error.rule.should_not be_nil
+      error.location.to_s.should eq "source.cr:1:1"
+      error.message.should eq "Possible forgotten debugger statement detected"
+    end
+  end
+end

spec/ameba/rule/empty_expression_spec.cr

@@ -0,0 +1,85 @@
+require "../../spec_helper"
+
+module Ameba
+  subject = Rule::EmptyExpression.new
+
+  def it_detects_empty_expression(code)
+    it "detects empty expression" do
+      s = Source.new code
+      rule = Rule::EmptyExpression.new
+      rule.catch(s).should_not be_valid
+    end
+  end
+
+  describe Rule::EmptyExpression do
+    it "passes if there is no empty expression" do
+      s = Source.new %(
+        def method()
+        end
+
+        method()
+        method(1, 2, 3)
+        method(nil)
+
+        a = nil
+        a = ""
+        a = 0
+      )
+      subject.catch(s).should be_valid
+    end
+
+    it_detects_empty_expression %(())
+    it_detects_empty_expression %(((())))
+    it_detects_empty_expression %(a = ())
+    it_detects_empty_expression %((();()))
+    it_detects_empty_expression %(if (); end)
+    it_detects_empty_expression %(
+      if foo
+        1
+      elsif ()
+        2
+      end
+    )
+    it_detects_empty_expression %(
+      case foo
+      when :foo then ()
+      end
+    )
+    it_detects_empty_expression %(
+      case foo
+      when :foo then 1
+      else
+        ()
+      end
+    )
+    it_detects_empty_expression %(
+      case foo
+      when () then 1
+      end
+    )
+    it_detects_empty_expression %(
+      def method
+        a = 1
+        ()
+      end
+    )
+    it_detects_empty_expression %(
+      def method
+      rescue
+        ()
+      end
+    )
+
+    it "reports rule, location and message" do
+      s = Source.new %(
+        if ()
+        end
+      ), "source.cr"
+      subject.catch(s).should_not be_valid
+      error = s.errors.first
+      error.rule.should_not be_nil
+      error.location.to_s.should eq "source.cr:2:12"
+      error.message.should eq "Avoid empty expression '()'"
+    end
+  end
+end

spec/ameba/rule/large_numbers_spec.cr

@@ -0,0 +1,118 @@
+require "../../spec_helper"
+
+module Ameba
+  subject = Rule::LargeNumbers.new
+
+  private def it_transforms(number, expected)
+    it "transforms large number #{number}" do
+      s = Source.new number
+      Rule::LargeNumbers.new.catch(s).should_not be_valid
+      s.errors.first.message.should contain expected
+    end
+  end
+
+  describe Rule::LargeNumbers do
+    it "passes if large number does not require underscore" do
+      s = Source.new %q(
+        1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
+        16 17 18 19 20 30 40 50 60 70 80 90
+        100
+        1_000
+        10_000
+        100_000
+        200_000
+        300_000
+        400_000
+        500_000
+        600_000
+        700_000
+        800_000
+        900_000
+        1_000_000
+
+       -9_223_372_036_854_775_808
+        9_223_372_036_854_775_807
+
+        141_592_654
+        141_592_654.0
+        141_592_654.001
+        141_592_654.001_2
+        141_592_654.001_23
+        141_592_654.001_234
+        141_592_654.001_234_5
+
+        0b1101
+        0o123
+        0xFE012D
+        0xfe012d
+        0xfe012dd11
+
+        1_i8
+        12_i16
+        123_i32
+        1_234_i64
+
+        12_u8
+        123_u16
+        1_234_u32
+        9_223_372_036_854_775_808_u64
+        9_223_372_036_854_775_808.000_123_456_789_f64
+
+        +100_u32
+        -900_000_i32
+
+        1_234.5e-7
+        11_234e10_f32
+        +1.123
+        -0.000_5
+      )
+      subject.catch(s).should be_valid
+    end
+
+    it_transforms "10000", "10_000"
+    it_transforms "+10000", "+10_000"
+    it_transforms "-10000", "-10_000"
+
+    it_transforms "9223372036854775808", "9_223_372_036_854_775_808"
+    it_transforms "-9223372036854775808", "-9_223_372_036_854_775_808"
+    it_transforms "+9223372036854775808", "+9_223_372_036_854_775_808"
+
+    it_transforms "1_00000", "100_000"
+
+    it_transforms "1_23_i8", "123_i8"
+    it_transforms "1000_i16", "1_000_i16"
+    it_transforms "1000_i32", "1_000_i32"
+    it_transforms "1000_i64", "1_000_i64"
+
+    it_transforms "1_23_u8", "123_u8"
+    it_transforms "1000_u16", "1_000_u16"
+    it_transforms "1000_u32", "1_000_u32"
+    it_transforms "1000_u64", "1_000_u64"
+
+    it_transforms "123456_f32", "123_456_f32"
+    it_transforms "123456_f64", "123_456_f64"
+
+    it_transforms "123456.5e-7_f32", "123_456.5e-7_f32"
+    it_transforms "123456e10_f64", "123_456e10_f64"
+
+    it_transforms "123456.5e-7", "123_456.5e-7"
+    it_transforms "123456e10", "123_456e10"
+
+    it_transforms "3.00_1", "3.001"
+    it_transforms "3.0012", "3.001_2"
+    it_transforms "3.00123", "3.001_23"
+    it_transforms "3.001234", "3.001_234"
+    it_transforms "3.0012345", "3.001_234_5"
+
+    it "reports rule, pos and message" do
+      s = Source.new %q(
+         1200000
+      ), "source.cr"
+      subject.catch(s).should_not be_valid
+      error = s.errors.first
+      error.rule.should_not be_nil
+      error.location.to_s.should eq "source.cr:2:10"
+      error.message.should match /1_200_000/
+    end
+  end
+end

spec/ameba/rule/line_length_spec.cr

@@ -0,0 +1,33 @@
+require "../../spec_helper"
+
+module Ameba::Rule
+  subject = LineLength.new
+  long_line = "*" * 81
+
+  describe LineLength do
+    it "passes if all lines are shorter than 80 symbols" do
+      source = Source.new "short line"
+      subject.catch(source).should be_valid
+    end
+
+    it "passes if line consists of 79 symbols" do
+      source = Source.new "*" * 80
+      subject.catch(source).should be_valid
+    end
+
+    it "fails if there is at least one line longer than 79 symbols" do
+      source = Source.new long_line
+      subject.catch(source).should_not be_valid
+    end
+
+    it "reports rule, pos and message" do
+      source = Source.new long_line, "source.cr"
+      subject.catch(source).should_not be_valid
+
+      error = source.errors.first
+      error.rule.should eq subject
+      error.location.to_s.should eq "source.cr:1:81"
+      error.message.should eq "Line too long"
+    end
+  end
+end

spec/ameba/rule/literal_in_condition_spec.cr

@@ -0,0 +1,72 @@
+require "../../spec_helper"
+
+module Ameba::Rule
+  subject = LiteralInCondition.new
+
+  describe LiteralInCondition do
+    it "passes if there is not literals in conditional" do
+      s = Source.new %(
+        if a == 2
+          :ok
+        end
+
+        :ok unless b
+
+        case string
+        when "a"
+          :ok
+        when "b"
+          :ok
+        end
+
+        unless a.nil?
+          :ok
+        end
+      )
+      subject.catch(s).should be_valid
+    end
+
+    it "fails if there is a predicate in if conditional" do
+      s = Source.new %(
+        if "string"
+          :ok
+        end
+      )
+      subject.catch(s).should_not be_valid
+    end
+
+    it "fails if there is a predicate in unless conditional" do
+      s = Source.new %(
+        unless true
+          :ok
+        end
+      )
+      subject.catch(s).should_not be_valid
+    end
+
+    it "fails if there is a predicate in case conditional" do
+      s = Source.new %(
+        case [1, 2, 3]
+        when :array
+          :ok
+        when :not_array
+          :also_ok
+        end
+      )
+      subject.catch(s).should_not be_valid
+    end
+
+    it "reports rule, pos and message" do
+      s = Source.new %(
+        puts "hello" if true
+      ), "source.cr"
+      subject.catch(s).should_not be_valid
+
+      s.errors.size.should eq 1
+      error = s.errors.first
+      error.rule.should_not be_nil
+      error.location.to_s.should eq "source.cr:2:9"
+      error.message.should eq "Literal value found in conditional"
+    end
+  end
+end

spec/ameba/rule/literal_in_interpolation_spec.cr

@@ -0,0 +1,41 @@
+require "../../spec_helper"
+
+module Ameba::Rule
+  subject = LiteralInInterpolation.new
+
+  describe LiteralInInterpolation do
+    it "passes with good interpolation examples" do
+      s = Source.new %q(
+        name = "Ary"
+        "Hello, #{name}"
+
+        "#{name}"
+
+        "Name size: #{name.size}"
+      )
+      subject.catch(s).should be_valid
+    end
+
+    it "fails if there is useless interpolation" do
+      [
+        %q("#{:Ary}"),
+        %q("#{[1, 2, 3]}"),
+        %q("#{true}"),
+        %q("#{false}"),
+        %q("here are #{4} cats"),
+      ].each do |str|
+        subject.catch(Source.new str).should_not be_valid
+      end
+    end
+
+    it "reports rule, pos and message" do
+      s = Source.new %q("#{4}"), "source.cr"
+      subject.catch(s).should_not be_valid
+
+      error = s.errors.first
+      error.rule.should_not be_nil
+      error.location.to_s.should eq "source.cr:1:1"
+      error.message.should eq "Literal value found in interpolation"
+    end
+  end
+end

spec/ameba/rule/method_names_spec.cr

@@ -0,0 +1,55 @@
+require "../../spec_helper"
+
+module Ameba
+  subject = Rule::MethodNames.new
+
+  private def it_reports_method_name(code, expected)
+    it "reports method name #{expected}" do
+      s = Source.new code
+      Rule::MethodNames.new.catch(s).should_not be_valid
+      s.errors.first.message.should contain expected
+    end
+  end
+
+  describe Rule::MethodNames do
+    it "passes if method names are underscore-cased" do
+      s = Source.new %(
+        class Person
+          def first_name
+          end
+
+          def date_of_birth
+          end
+
+          def homepage_url
+          end
+
+          def valid?
+          end
+
+          def name
+          end
+        end
+      )
+      subject.catch(s).should be_valid
+    end
+
+    it_reports_method_name %(def firstName; end), "first_name"
+    it_reports_method_name %(def date_of_Birth; end), "date_of_birth"
+    it_reports_method_name %(def homepageURL; end), "homepage_url"
+
+    it "reports rule, pos and message" do
+      s = Source.new %(
+        def bad_Name
+        end
+      ), "source.cr"
+      subject.catch(s).should_not be_valid
+      error = s.errors.first
+      error.rule.should_not be_nil
+      error.location.to_s.should eq "source.cr:2:9"
+      error.message.should eq(
+        "Method name should be underscore-cased: bad_name, not bad_Name"
+      )
+    end
+  end
+end

spec/ameba/rule/negated_conditions_in_unless_spec.cr

@@ -0,0 +1,68 @@
+require "../../spec_helper"
+
+module Ameba::Rule
+  subject = NegatedConditionsInUnless.new
+
+  describe NegatedConditionsInUnless do
+    it "passes with a unless without negated condition" do
+      s = Source.new %(
+        unless a
+          :ok
+        end
+
+        :ok unless b
+
+        unless s.empty?
+          :ok
+        end
+      )
+      subject.catch(s).should be_valid
+    end
+
+    it "fails if there is a negated condition in unless" do
+      s = Source.new %(
+        unless !a
+          :nok
+        end
+      )
+      subject.catch(s).should_not be_valid
+    end
+
+    it "fails if one of AND conditions is negated" do
+      s = Source.new %(
+        unless a && !b
+          :nok
+        end
+      )
+      subject.catch(s).should_not be_valid
+    end
+
+    it "fails if one of OR conditions is negated" do
+      s = Source.new %(
+        unless a || !b
+          :nok
+        end
+      )
+      subject.catch(s).should_not be_valid
+    end
+
+    it "fails if one of inner conditions is negated" do
+      s = Source.new %(
+        unless a && (b || !c)
+          :nok
+        end
+      )
+      subject.catch(s).should_not be_valid
+    end
+
+    it "reports rule, pos and message" do
+      s = Source.new ":nok unless !s.empty?", "source.cr"
+      subject.catch(s).should_not be_valid
+
+      error = s.errors.first
+      error.rule.should_not be_nil
+      error.location.to_s.should eq "source.cr:1:1"
+      error.message.should eq "Avoid negated conditions in unless blocks"
+    end
+  end
+end

spec/ameba/rule/predicate_name_spec.cr

@@ -0,0 +1,45 @@
+require "../../spec_helper"
+
+module Ameba::Rule
+  subject = PredicateName.new
+
+  describe PredicateName do
+    it "passes if predicate name is correct" do
+      s = Source.new %q(
+        def valid?(x)
+        end
+
+        class Image
+          def picture?(x)
+          end
+        end
+      )
+      subject.catch(s).should be_valid
+    end
+
+    it "fails if predicate name is wrong" do
+      s = Source.new %q(
+        def is_valid?(x)
+        end
+      )
+      subject.catch(s).should_not be_valid
+    end
+
+    it "reports rule, pos and message" do
+      s = Source.new %q(
+        class Image
+          def has_picture?(x)
+            true
+          end
+        end
+      ), "source.cr"
+      subject.catch(s).should_not be_valid
+
+      error = s.errors.first
+      error.rule.should_not be_nil
+      error.location.to_s.should eq "source.cr:3:11"
+      error.message.should eq(
+        "Favour method name 'picture?' over 'has_picture?'")
+    end
+  end
+end

spec/ameba/rule/trailing_blank_lines_spec.cr

@@ -0,0 +1,37 @@
+require "../../spec_helper"
+
+module Ameba::Rule
+  subject = TrailingBlankLines.new
+
+  describe TrailingBlankLines do
+    it "passes if there is no blank lines at the end" do
+      source = Source.new "no-blankline"
+      subject.catch(source).should be_valid
+    end
+
+    it "fails if there is a blank line at the end of a source" do
+      source = Source.new "a = 1\n \n "
+      subject.catch(source).should_not be_valid
+    end
+
+    it "passes if source is empty" do
+      source = Source.new ""
+      subject.catch(source).should be_valid
+    end
+
+    it "passes if last line is not blank" do
+      source = Source.new "\n\n\n puts 22"
+      subject.catch(source).should be_valid
+    end
+
+    it "reports rule, pos and message" do
+      source = Source.new "a = 1\n\n ", "source.cr"
+      subject.catch(source).should_not be_valid
+
+      error = source.errors.first
+      error.rule.should_not be_nil
+      error.location.to_s.should eq "source.cr:3:1"
+      error.message.should eq "Blank lines detected at the end of the file"
+    end
+  end
+end

spec/ameba/rule/trailing_whitespace_spec.cr

@@ -0,0 +1,27 @@
+require "../../spec_helper"
+
+module Ameba::Rule
+  subject = TrailingWhitespace.new
+
+  describe TrailingWhitespace do
+    it "passes if all lines do not have trailing whitespace" do
+      source = Source.new "no-whispace"
+      subject.catch(source).should be_valid
+    end
+
+    it "fails if there is a line with trailing whitespace" do
+      source = Source.new "whitespace at the end "
+      subject.catch(source).should_not be_valid
+    end
+
+    it "reports rule, pos and message" do
+      source = Source.new "a = 1\n b = 2 ", "source.cr"
+      subject.catch(source).should_not be_valid
+
+      error = source.errors.first
+      error.rule.should_not be_nil
+      error.location.to_s.should eq "source.cr:2:7"
+      error.message.should eq "Trailing whitespace detected"
+    end
+  end
+end

spec/ameba/rule/type_names_spec.cr

@@ -0,0 +1,60 @@
+require "../../spec_helper"
+
+module Ameba
+  subject = Rule::TypeNames.new
+
+  private def it_reports_name(code, expected)
+    it "reports type name #{expected}" do
+      s = Source.new code
+      Rule::TypeNames.new.catch(s).should_not be_valid
+      s.errors.first.message.should contain expected
+    end
+  end
+
+  describe Rule::TypeNames do
+    it "passes if type names are camelcased" do
+      s = Source.new %(
+        class ParseError < Exception
+        end
+
+        module HTTP
+          class RequestHandler
+          end
+        end
+
+        alias NumericValue = Float32 | Float64 | Int32 | Int64
+
+        lib LibYAML
+        end
+
+        struct TagDirective
+        end
+
+        enum Time::DayOfWeek
+        end
+      )
+      subject.catch(s).should be_valid
+    end
+
+    it_reports_name "class My_class; end", "MyClass"
+    it_reports_name "module HTT_p; end", "HTTP"
+    it_reports_name "alias Numeric_value = Int32", "NumericValue"
+    it_reports_name "lib Lib_YAML; end", "LibYAML"
+    it_reports_name "struct Tag_directive; end", "TagDirective"
+    it_reports_name "enum Time_enum::Day_of_week; end", "TimeEnum::DayOfWeek"
+
+    it "reports rule, pos and message" do
+      s = Source.new %(
+        class My_class
+        end
+      ), "source.cr"
+      subject.catch(s).should_not be_valid
+      error = s.errors.first
+      error.rule.should_not be_nil
+      error.location.to_s.should eq "source.cr:2:9"
+      error.message.should eq(
+        "Type name should be camelcased: MyClass, but it was My_class"
+      )
+    end
+  end
+end

spec/ameba/rule/unless_else_spec.cr

@@ -0,0 +1,44 @@
+require "../../spec_helper"
+
+module Ameba::Rule
+  subject = UnlessElse.new
+
+  describe UnlessElse do
+    it "passes if unless hasn't else" do
+      s = Source.new %(
+        unless something
+          :ok
+        end
+      )
+      subject.catch(s).should be_valid
+    end
+
+    it "fails if unless has else" do
+      s = Source.new %(
+        unless something
+          :one
+        else
+          :two
+        end
+      )
+      subject.catch(s).should_not be_valid
+    end
+
+    it "reports rule, pos and message" do
+      s = Source.new %(
+        unless something
+          :one
+        else
+          :two
+        end
+      ), "source.cr"
+      subject.catch(s).should_not be_valid
+
+      error = s.errors.first
+      error.should_not be_nil
+      error.rule.should_not be_nil
+      error.location.to_s.should eq "source.cr:2:9"
+      error.message.should eq "Favour if over unless with else"
+    end
+  end
+end

spec/ameba/rule/variable_names_spec.cr

@@ -0,0 +1,61 @@
+require "../../spec_helper"
+
+module Ameba
+  subject = Rule::VariableNames.new
+
+  private def it_reports_var_name(code, expected)
+    it "reports method name #{expected}" do
+      s = Source.new code
+      Rule::VariableNames.new.catch(s).should_not be_valid
+      s.errors.first.message.should contain expected
+    end
+  end
+
+  describe Rule::VariableNames do
+    it "passes if var names are underscore-cased" do
+      s = Source.new %(
+        class Greeting
+          @@default_greeting = "Hello world"
+
+          def initialize(@custom_greeting = nil)
+          end
+
+          def print_greeting
+            greeting = @custom_greeting || @@default_greeting
+            puts greeting
+          end
+        end
+      )
+      subject.catch(s).should be_valid
+    end
+
+    it_reports_var_name %(myBadNamedVar = 1), "my_bad_named_var"
+    it_reports_var_name %(wrong_Name = 'y'), "wrong_name"
+
+    it_reports_var_name %(
+      class Greeting
+        def initialize(@badNamed = nil)
+        end
+      end
+    ), "bad_named"
+
+    it_reports_var_name %(
+      class Greeting
+        @@defaultGreeting = "Hello world"
+      end
+    ), "default_greeting"
+
+    it "reports rule, pos and message" do
+      s = Source.new %(
+        badName = "Yeah"
+      ), "source.cr"
+      subject.catch(s).should_not be_valid
+      error = s.errors.first
+      error.rule.should_not be_nil
+      error.location.to_s.should eq "source.cr:2:9"
+      error.message.should eq(
+        "Var name should be underscore-cased: bad_name, not badName"
+      )
+    end
+  end
+end