Add tests for the core

lib/chervil/core.rb

@@ -34,7 +34,8 @@ module Chervil
 
     def self.arity_check(args, expected_count)
       if args.size != expected_count
-        ::Chervil::Error.new("Expected #{expected_count} arguments but received #{args.size}")
+        s = expected_count == 1 ? '' : 's'
+        Error.new("Expected #{expected_count} argument#{s} but received #{args.size}")
       else
         nil
       end
@@ -52,7 +53,14 @@ module Chervil
       ">=" => Proc.new { |args| type_check(args, Float) || compare_pairs(args, :>=) },
       "and" => Proc.new { |args| !(args.include?(false)) },
       "or" => Proc.new { |args| args.any? { |arg| !!arg == true } },
-      "not" => Proc.new { |args| arity_check(args, 1) || args.first == false ? true : false },
+      "not" => Proc.new do |args|
+        error = arity_check(args, 1)
+        if error.nil?
+          args.first == false ? true : false
+        else
+          error
+        end
+      end,
     }
   end
 end

spec/core_spec.rb

@@ -0,0 +1,41 @@
+module Chervil
+  RSpec.describe Core do
+    it 'does arithmetic' do
+      expect(Core::CORE['+'].call([1.0, 2.0])).to eq(3.0)
+      expect(Core::CORE['-'].call([3.0, 1.0])).to eq(2.0)
+      expect(Core::CORE['*'].call([2.0, 3.0])).to eq(6.0)
+      expect(Core::CORE['/'].call([6.0, 2.0])).to eq(3.0)
+    end
+
+    it 'compares values' do
+      expect(Core::CORE['='].call([1.0, 2.0])).to eq(false)
+      expect(Core::CORE['='].call([1.0, 1.0])).to eq(true)
+      expect(Core::CORE['<'].call([2.0, 1.0])).to eq(false)
+      expect(Core::CORE['<'].call([2.0, 3.0])).to eq(true)
+      expect(Core::CORE['>'].call([2.0, 1.0])).to eq(true)
+      expect(Core::CORE['>'].call([2.0, 3.0])).to eq(false)
+      expect(Core::CORE['<='].call([2.0, 1.0])).to eq(false)
+      expect(Core::CORE['<='].call([2.0, 2.0])).to eq(true)
+      expect(Core::CORE['>='].call([2.0, 2.0])).to eq(true)
+      expect(Core::CORE['>='].call([2.0, 3.0])).to eq(false)
+      expect(Core::CORE['and'].call([2.0, 3.0])).to eq(true)
+      expect(Core::CORE['and'].call([2.0, 3.0, false])).to eq(false)
+      expect(Core::CORE['or'].call([2.0, 3.0, false])).to eq(true)
+      expect(Core::CORE['or'].call([false, false])).to eq(false)
+      expect(Core::CORE['not'].call([1.0])).to eq(false)
+      expect(Core::CORE['not'].call([false])).to eq(true)
+    end
+
+    it 'returns an error if argument has the wrong type' do
+      expect(Core::CORE['+'].call([1.0, "hello"])).to eq(
+        Error.new("Expected an argument of type number but got string")
+      )
+    end
+
+    it 'returns an error if given the wrong number of arguments' do
+      expect(Core::CORE['not'].call([1.0, 2.0])).to eq(
+        Error.new("Expected 1 argument but received 2")
+      )
+    end
+  end
+end