Update valdator unit test to validate that the line and column number is included in the error output

[kehoecj]

Description

Add a check to the error output in the validator unit test to ensure that it contains line and column number output in the error message. The test should fail if line/column are not included in the output. This will help internal and external contributors who are adding new types.

[kehoecj]

This is blocked until #27 is implemented