Tests for UserDB APIs

[HadleyKing]

• [x] #207
• [ ] #185
• [ ] #186
• [ ] #187
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• [ ] #189
• [ ] #190
• [ ] #191
• [ ] #192
• [ ] #193
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• [x] #200
• [ ] #201
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• [ ] #203
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• [ ] #206
• [x] #246
• [x] #247
• [x] #248

[Reeya123]

Do we close this issue? @HadleyKing

Not sure how much we progressed with these.