unittest: fix length assertion

[zhangzujian]

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What type of this PR

Examples of user facing changes:

• Tests

Which issue(s) this PR fixes:

Fixes #(issue-number)

[github-actions]

• The commit message should be more descriptive and informative.
• In line 6, the assertion is comparing the length of args with itself instead of wants. It should be changed to Expect(len(args)).To(Equal(len(wants))).
• In line 16, the assertion is comparing the length of args with itself instead of wants. It should be changed to Expect(args).To(HaveLen(len(wants))).
• In line 31, the assertion is comparing the length of args with itself instead of wants. It should be changed to Expect(args).To(HaveLen(len(wants))).