Adding error message if the function name is too long

[tbhagwat16]

Test case gets failed if the testing function name is too long.

Description

I have faced an issue when I have imported NewDockerCluster for creating vault client. My testing function name was too long [more than 64 characters] So I was getting below error.

TODO only if you're a HashiCorp employee

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[heatherezell]

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