Corner case cheat sheet in Java
These are combinations of input value that tend to trigger corner cases more often.
Use them in your unit and integration tests.
Cheat sheet numbers
| Expression | Actual result |
|---|---|
| 1000000000 + 2000000000 | -1294967296 |
| 0.01 + 0.09 | 0.09999999999999999 |
| 0.01 + 0.05 | 0.060000000000000005 |
| 0.01 + 0.02 + 0.03 | 0.06 |
| 0.03 + 0.02 + 0.01 | 0.060000000000000005 |
| (double) 9007199254740993L | 9007199254740992.0 |
| 9007199254740992.0 + 1.0 | 9007199254740992.0 |
| 9007199254740992.0 + 3.0 | 9007199254740996.0 |
Cheat sheet text
| String | Why |
|---|---|
| Allô (French telephone hello) | ISO 8859-1 |
| € (euro) | Since 1996, not in 8859-1 |
| Hallå (Swedish hello) | Mostly ASCII |
| Здравствуйте (Russian hello) | Looks a bit like ASCII |
| こんにちは (Japanese hello) | No ASCII whatsoever |
| ≠ (different) ⇔ (iff) ∑ (sum) | Math symbols |
| \ (backslash) " (double) ' (single) | Java/SQL/... special chars |
| & (ampersand) < (lower than) | XML special chars |
| ` (slant) # (number sign) $ (dollar) | Shell special chars |
Cheat sheet dates and time
| Expression | Actual result |
|---|---|
| From 2017-03-12 00:00 to 2017-03-13 00:00 |
23 hours in America/New_York |
| From 2017-03-26 00:00 to 2017-03-27 00:00 |
23 hours in Europe/Paris |
| From 2017-10-29 00:00 to 2017-10-30 00:00 |
25 hours in Europe/Paris |
| From 2017-11-05 00:00 to 2017-11-06 00:00 |
25 hours in America/New_York |
