Writing tests for functions with optional return types
We have learned that test functions must not specify a return type. But we have also learned that test function properties can be marked with the symbol ? when the test logic deals with functions with optional return types. To demonstrate this, consider the following greet function:
fn greet(name string) ?string {
if name != '' {
return 'Hello $name!'
}
return error('name not provided')
}
The greet function returns a ?string type. This means greet will return a string value only when a non-empty name is provided to it as an input argument. If the name is an empty string, it will return an error with the message name not provided. The following code shows the test case when the name parameter is provided with a non-empty string:
fn test_greet_given_a_name...