On Tuesday, 31 July 2018 at 08:28:01 UTC, Ky-Anh Huynh wrote:
Hi,
Can I define a new quick function to use inside a unittest
block?
I have the following code:
[code]
auto foo(string[] sta) {
return sta;
}
auto bar(string[] sta) {
return sta;
}
auto h(string[] sta) {
return sta.foo.bar;
}
unittest {
import std.format;
auto f = (string[] sta) => sta.foo.bar;
auto g(string[] sta) {
return sta.foo.bar;
}
assert(f(["test"]) == ["test"]);
assert(g(["test"]) == ["test"]);
assert(["test"].h == ["test"]);
assert(["test"].g == ["test"]);
}
[/code]
(Src:
https://gist.github.com/icy/64ec1838929d448d9f874d1e8261e56a)
The last test will fail: Error: no property g for type string[]
Please advise.
From https://dlang.org/spec/function.html#pseudo-member:
"A free function can be called with a syntax that looks as if the
function were a member function of its first parameter type."
A function defined in a function scope (which a unittest block
is), is not a free function, and so does not benefit from UFCS.
There is an explanation for why at the bottom of the above page:
"The reason why local symbols are not considered by UFCS, is to
avoid unexpected name conflicts."
If you need a function that's available for UFCS in a unittest
but is not there in a non-unittest context, use a version block:
version (unittest) {
auto fun(string[] s) { return s }
}
And if you need something with a context:
version (unittest) {
string delegate (string) test;
}
unittest {
string s1 = "foo";
test = s => s ~ s1;
"foo".test;
}
--
Simen
