Add aboutEqual expectations (#61)

* Add aboutEqual expectations

* Deprecate .eq

* Update readme example

README.md

@@ -490,6 +490,7 @@ There are a number of different expectations you can use.
 | Expectation | Description | Example |
 |----------------------|-----------------------------------------------------------|-----------------------------------------------------------------|
 | **`equal`**/**`eq`** | Basic `==` equality check | `expect( a ).to.equal( b )` |
+| **`aboutEqual`** | Basic `==` equality check, with a tolerance | `expect( 0.999 ).to.aboutEqual( 1 )` |
 | **`beLessThan`** | Basic `<` comparison | `expect( 5 ).to.beLessThan( 6 )` |
 | **`beGreaterThan`** | Basic `>` comparison | `expect( 10 ).to.beGreaterThan( 1 )` |
 | **`beBetween`** | Expects the subject to be less than min, and greater than max | `expect( 5 ).to.beBetween( 3, 7 )` |

lua/gluatest/expectations/negative.lua

@@ -17,12 +17,25 @@ return function( subject, ... )
 
  local i = expectations
 
- function expectations.eq( comparison )
+ function expectations.equal( comparison )
  if subject == comparison then
  i.expected( "to not equal '%s'", comparison )
  end
  end
- expectations.equal = expectations.eq
+
+ function expectations.eq( comparison )
+ GLuaTest.DeprecatedNotice( "toNot.eq( value )", "toNot.equal( value )" )
+ return expectations.equal( comparison )
+ end
+
+ function expectations.aboutEqual( comparison )
+ local tolerance = args[1] or 0.00001
+ local difference = math.abs( subject - comparison )
+
+ if difference <= tolerance then
+ i.expected( "to not be within '%s' of '%s' - found a difference of '%s'", tolerance, comparison, difference )
+ end
+ end
 
  function expectations.beLessThan( comparison )
  if subject < comparison then

lua/gluatest/expectations/positive.lua

@@ -17,12 +17,25 @@ return function( subject, ... )
 
  local i = expectations
 
- function expectations.eq( comparison )
+ function expectations.equal( comparison )
  if subject ~= comparison then
  i.expected( "to equal '%s'", comparison )
  end
  end
- expectations.equal = expectations.eq
+
+ function expectations.eq( comparison )
+ GLuaTest.DeprecatedNotice( "to.eq( value )", "to.equal( value )" )
+ return expectations.equal( comparison )
+ end
+
+ function expectations.aboutEqual( comparison )
+ local tolerance = args[1] or 0.00001
+ local difference = math.abs( subject - comparison )
+
+ if difference > tolerance then
+ i.expected( "to be within '%s' of '%s' - found a difference of '%s'", tolerance, comparison, difference )
+ end
+ end
 
  function expectations.beLessThan( comparison )