Ability to add custom assertions.

[AbhitejJohn]

Description

Often times, the default set of assertion APIs are not sufficient to satisfy a wide range of requirements for unit test writers. In most of these situations users end up having utility methods to address this need reducing discoverability in a test suite. If the test framework provides an extensibility in the assertion infrastructure itself, custom assertion functionality can be

• Easily accessed
• Easily organized and
• Possibly shared with the community.

Filing this issue to plug in an extensibility model to address this.

[AbhitejJohn]

Here is the design doc that details the solution.

[AbhitejJohn]

Fixed with #117