fix: Fix unit tests

[congminh1254]

Instead of listening for writing stream end from the API request, we should wait for close event of the file stream to make sure that the file writing is finished.

[coveralls]

Pull Request Test Coverage Report for Build 4060319580

• 18 of 18 (100.0%) changed or added relevant lines in 4 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 86.392%

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Totals
Change from base Build 3959265428:	0%
Covered Lines:	3975
Relevant Lines:	4462

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💛 - Coveralls