A nullary (zero-parameter) "function" that is a bit friendlier to testing.
This is a variant of () => A -- that is, a function that takes no parameters and returns an A. In practice, that isn't quite true: where () => A is lazy (it is not evaluated until you call it), this one is strict (you pass the result in as a parameter).
In exchange, this is more usable and reproducible for test environments. Its hashCode and equals are based on those of the passed-in value (so they are consistent and reproducible), and its toString nicely displays the result that will always be returned.
It is reflexive: for any instance x of type Any, x.equals(x) should return true.
It is symmetric: for any instances x and y of type Any, x.equals(y) should return true if and only if y.equals(x) returns true.
It is transitive: for any instances x, y, and z of type Any if x.equals(y) returns true and y.equals(z) returns true, then x.equals(z) should return true.
If you override this method, you should verify that your implementation remains an equivalence relation. Additionally, when overriding this method it is usually necessary to override hashCode to ensure that objects which are "equal" (o1.equals(o2) returns true) hash to the same scala.Int. (o1.hashCode.equals(o2.hashCode)).
Value parameters
that
the object to compare against this object for equality.
Attributes
Returns
true if the receiver object is equivalent to the argument; false otherwise.
The default hashing algorithm is platform dependent.
Note that it is allowed for two objects to have identical hash codes (o1.hashCode.equals(o2.hashCode)) yet not be equal (o1.equals(o2) returns false). A degenerate implementation could always return 0. However, it is required that if two objects are equal (o1.equals(o2) returns true) that they have identical hash codes (o1.hashCode.equals(o2.hashCode)). Therefore, when overriding this method, be sure to verify that the behavior is consistent with the equals method.