Error handling is not sufficient

[AljoschaK]

There are multiple errors that are not sufficiently handled if the user does the wrong action: Instead a "Internal Server Error" is shown. These Errors should be caught. Please try to find any occurences of a user action, that can cause an Error and put an informative Warning instead. Known examples that need to be handled are (but there might be more): The same parameter is selected twice in the scatter plot When the user selects the same parameter for x and y in the scatter plot, this causes an Error. Instead The User should see the warning "x and y cannot be the same parameter. Please select two different parameters." No Plot selected If in the plotting tab, the user selects no plot (neither scatter plot or heat map) and presses "plot data", there will be an error. Instad the user should see a warning "Please select plot type." Missing Data for a parameter If a parameter contains no data at all, and a plot is created this will show an error. This can be reproduced the following way:

• stop the docker image

• Copy the dataset.csv and entities.csv from "dataset_examples" to the "input" directory

• If the docker is started now, the data will be loaded and everything works normally

• Instead, open the dataset.csv and delete all content, then save the empty file. (still in the input directory)

• When the docker is started now, Medex thinks, all parameters which are described in the entities.csv are present. They can be selected in the plotting, heatmap and so on.

• However, there is no actual data for these parameters, so once a plot is created, an empty datastructure is returned. This seems to cause an error.

• However, this case should instead cause a warning shown to the user: "Parameter xy does not contain any values. Please select another parameter"

[AljoschaK]

An appropriate Warning needs to exist also for the boxplot, if one or more values are not selected, we get an uncatched error at the moment

[AljoschaK]

Coplot Tab The user can select two times the same category or same numeric, but this will lead to an uncatched error.

[AljoschaK]

Scatter plot Here as well we get an error when selecting two times the same numeric parameter.

[AljoschaK]

In addition to no values at all, we also need to handle the situation where one variable is completely fine, but the other one is empty: But if only one parameter has no values, but the other one has data, the app will break.

This can be simulated by:

• Copy the dataset.csv and entities.csv from "dataset_examples" to the "input" directory (both files with all data)

• Open entities.csv with an editor and add the line "The_empty_variable,Double" , then safe

• start the docker

• Try to plot any variable against the "The_empty_variable", which is listed but does not have any values, while the other variable (e.g. Delta0) does have values

This will break the app. This should be handled.

[AljoschaK]

All known errors that could happen upon user interaction were addressed.