Steps to reproduce:
- Create a data set containing multiple cases per algorithm but also missing algorithm performance
- Create a challenge object
Expected behavior: an error should be thrown
```
data=rbind(
data.frame(alg_name="A1", value=0.8, case="C1"),
data.frame(alg_name="A1", value=0.8, case="C1"),
data.frame(alg_name="A2", value=0.6, case="C2"),
data.frame(alg_name="A2", value=0.6, case="C2")
)
expect_error(as.challenge(data, algorithm="alg_name", case="case", value="value", smallBetter=FALSE),
"Case(s) (C1, C2) appear(s) more than once for the same algorithm", fixed=TRUE)
}
```