Use custom error instead of ArgumentError

Using ArgumentError sounds like a good idea since we received invalid
argument to this method, but this exception is suppose to be when you
pass the wrong number of arguments or missing keywords.

Author: stoivo

lib/css_parser.rb

@@ -15,6 +15,9 @@
 require 'css_parser/parser'
 
 module CssParser
+  class Error < StandardError; end
+  class EmptyValueError < Error; end
+
   # Merge multiple CSS RuleSets by cascading according to the CSS 2.1 cascading rules
   # (http://www.w3.org/TR/REC-CSS2/cascade.html#cascading-order).
   #

lib/css_parser/parser.rb

@@ -199,7 +199,7 @@ def add_rule!(*args, selectors: nil, block: nil, filename: nil, offset: nil, med
         )
 
         add_rule_set!(rule_set, media_types)
-      rescue ArgumentError => e
+      rescue CssParser::Error => e
         raise e if @options[:rule_set_exceptions]
       end
     end

lib/css_parser/rule_set/declarations.rb

@@ -16,7 +16,7 @@ def value=(value)
           value = value.to_s.sub(/\s*;\s*\Z/, '')
           self.important = !value.slice!(CssParser::IMPORTANT_IN_PROPERTY_RX).nil?
           value.strip!
-          raise ArgumentError, 'value is empty' if value.empty?
+          raise EmptyValueError, 'value is empty' if value.empty?
 
           @value = value.freeze
         end
@@ -67,10 +67,12 @@ def []=(property, value)
         elsif value.to_s.strip.empty?
           delete property
         else
-          declarations[property] = Value.new(value)
+          begin
+            declarations[property] = Value.new(value)
+          rescue EmptyValueError => e
+            raise e.exception, "#{property} #{e.message}"
+          end
         end
-      rescue ArgumentError => e
-        raise e.exception, "#{property} #{e.message}"
       end
       alias add_declaration! []=
 

test/rule_set/declarations/test_value.rb

@@ -8,17 +8,17 @@ class RuleSetProperyTest < Minitest::Test
   describe '.new' do
     describe 'with invalid value' do
       it 'raises an error when empty' do
-        exception = assert_raises(ArgumentError) { CssParser::RuleSet::Declarations::Value.new('  ') }
+        exception = assert_raises(CssParser::EmptyValueError) { CssParser::RuleSet::Declarations::Value.new('  ') }
         assert_equal 'value is empty', exception.message
       end
 
       it 'raises an error when nil' do
-        exception = assert_raises(ArgumentError) { CssParser::RuleSet::Declarations::Value.new(nil) }
+        exception = assert_raises(CssParser::EmptyValueError) { CssParser::RuleSet::Declarations::Value.new(nil) }
         assert_equal 'value is empty', exception.message
       end
 
       it 'raises an error when contains only important declaration' do
-        exception = assert_raises(ArgumentError) { CssParser::RuleSet::Declarations::Value.new(' !important; ') }
+        exception = assert_raises(CssParser::EmptyValueError) { CssParser::RuleSet::Declarations::Value.new(' !important; ') }
         assert_equal 'value is empty', exception.message
       end
     end
@@ -103,7 +103,13 @@ class RuleSetProperyTest < Minitest::Test
       assert_equal true, CssParser::RuleSet::Declarations::Value.new('value').value.frozen?
     end
 
-    it 'raises an exception when the value is empty' do
+    it 'raises an EmptyValueError when an empty string is passed' do
+      assert_raises CssParser::EmptyValueError do
+        CssParser::RuleSet::Declarations::Value.new ""
+      end
+    end
+
+    it 'raises an ArgumentError when no argument is supplied' do
       assert_raises ArgumentError do
         CssParser::RuleSet::Declarations::Value.new
       end

test/rule_set/test_declarations.rb

@@ -73,9 +73,9 @@ class RuleSetDeclarationsTest < Minitest::Test
     it 'raises an exception including the property when the value is empty' do
       declarations = CssParser::RuleSet::Declarations.new
 
-      assert_raises ArgumentError do
+      assert_raises CssParser::EmptyValueError do
         declarations['foo'] = '!important'
-      rescue ArgumentError => e
+      rescue CssParser::EmptyValueError => e
         assert_equal e.message, 'foo value is empty'
         raise e
       end

test/test_css_parser_misc.rb

@@ -229,9 +229,10 @@ def test_enumerator_nonempty
 
   def test_catching_argument_exceptions_for_add_rule
     cp_with_exceptions = Parser.new(rule_set_exceptions: true)
-    assert_raises ArgumentError, 'background-color value is empty' do
+    error = assert_raises CssParser::EmptyValueError do
       cp_with_exceptions.add_rule!(selectors: 'body', block: 'background-color: !important')
     end
+    assert_equal error.message, 'background-color value is empty'
 
     cp_without_exceptions = Parser.new(rule_set_exceptions: false)
     cp_without_exceptions.add_rule!(selectors: 'body', block: 'background-color: !important')
@@ -240,12 +241,13 @@ def test_catching_argument_exceptions_for_add_rule
   def test_catching_argument_exceptions_for_add_rule_positional
     cp_with_exceptions = Parser.new(rule_set_exceptions: true)
 
-    assert_raises ArgumentError, 'background-color value is empty' do
+    error = assert_raises CssParser::EmptyValueError do
       _, err = capture_io do
         cp_with_exceptions.add_rule!('body', 'background-color: !important')
       end
       assert_includes err, "DEPRECATION"
     end
+    assert_equal error.message, 'background-color value is empty'
 
     cp_without_exceptions = Parser.new(rule_set_exceptions: false)
     _, err = capture_io do
@@ -257,12 +259,13 @@ def test_catching_argument_exceptions_for_add_rule_positional
   def test_catching_argument_exceptions_for_add_rule_with_offsets
     cp_with_exceptions = Parser.new(capture_offsets: true, rule_set_exceptions: true)
 
-    assert_raises ArgumentError, 'background-color value is empty' do
+    error = assert_raises CssParser::EmptyValueError do
       _, err = capture_io do
         cp_with_exceptions.add_rule_with_offsets!('body', 'background-color: !important', 'inline', 1)
       end
       assert_includes err, "DEPRECATION"
     end
+    assert_equal error.message, 'background-color value is empty'
 
     cp_without_exceptions = Parser.new(capture_offsets: true, rule_set_exceptions: false)
     _, err = capture_io do