数据库单元测试

Question

I am hoping to get some advice on a unit test I am writing for to test some db entries.

The function I am testing seeds the database if no records are found.

func Seed(db *gorm.DB) {
    var data []Data
    db.Find(&data)

    if len(data) == 0 {
      // do seed default data
    }

}

What I can't quite seem to get going is the test for that if len test. I am using a test db so I can nuke it whenever so it is not an issue if I just need to force an empty DB on the function.

The function itself works and I just want to make sure I get that covered.

Any advice would be great.

Thanks!

Answer 1

It really depends, there are so many ways of addressing this based on your risk level and the amount of time you want to invest to mitigate those risks.

• You could write a unit test that asserts your able to detect and act on users logic (ie seeding when empty and ignoring when full) without any database.
• If you would like to test the logic as well as your programs ability to speak to mysql correctly through the gorm library you could:
  • Have a test where you call Seed with no users in the DB, after calling it your test could select from Users and make sure there are the expected entries created from len(users) == 0 conditional
  • Have a test where the test creates a single entry and calls Seed, after which asserting that underlying tables are empty.

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It can get more complicated. If Seed is selecting a subset of data than your test could insert 2 users, one that qualifies and one that doesnt', and make sure that no new users are Seeded.