add positive test for the _is_inchikey method in CompoundIdentifier class

[adebisi4145]

…lass

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Description

The _is_inchikey method in CompoundIdentifier class checks whether a given string is a valid InChIKey. This method checks whether the string provided is exactly 27 characters long, splits the string into 3 parts using hyphen (-) as the seperator and then ensure that the first part has 14 characters, the second part has 10 characters, and the third part has 1 character.

This PR adds positive test for the _is_inchikey method

Changes to be made

• Add positive test case for _is_inchikey

• Test the following valid 27-character InChIKeys:
  Aspirin: BSYNRYMUTXBXSQ-UHFFFAOYSA-N
  Caffeine: BQJCRHHNABKAKU-KBQPJGBKSA-N
  Ibuprofen: ZJPODVODJYKFHM-UHFFFAOYSA-N

Status

• I added the positive test case for _is_inchikey
• I ran all tests locally here

To do

If this is a work in progress, Replace this line with your next steps

Is this pull request related to any open issue? If yes, replace issueID below with the issue ID

Related to #1319

[adebisi4145]

Hello @DhanshreeA , @Malikbadmus I just discovered that the _is_inchikey method currently does not enforce case sensitivity in its validation