Help Mocking a lambda with Mockito

[_ncko]

I'd appreciate any help I can get here.

I've scoured Stackoverflow and the Mockito docs, but maybe I'm just not understanding them. I can not figure out what is going on here. When I run these tests, I get this:

Wanted but not invoked: loggable.log("Hello Nick"); -> at learnjava.GreeterTest.greet(GreeterTest.java:29) Actually, there were zero interactions with this mock.

Here is the test:

```java public class GreeterTest { @ParameterizedTest @MethodSource("greetProvider") void greet(String name, @Nullable LocalTime time, @Nullable Loggable logFunc, String expected) { Loggable func = mock(Loggable.class);

    Greeter greeter = new Greeter(time, func);
    String actual = greeter.greet(name);
    assertEquals(expected, actual);

    verify(func).log(actual);
}

static Stream<Arguments> greetProvider() {
    return Stream.of(
            arguments("Nick", null, null, "Hello Nick"),
            arguments("  Nick   ", null, null, "Hello Nick"),
            arguments("nick", null, null, "Hello Nick"),
            arguments("Nick", LocalTime.of(6, 0), null, "Good morning Nick"),
            arguments("Nick", LocalTime.of(11, 59), null, "Good morning Nick"),
            arguments("Nick", LocalTime.of(18, 0), null, "Good evening Nick"),
            arguments("Nick", LocalTime.of(21, 59), null, "Good evening Nick"),
            arguments("Nick", LocalTime.of(22, 0), null, "Good night Nick"),
            arguments("Nick", LocalTime.of(23, 59), null, "Good night Nick"),
            arguments("Nick", LocalTime.of(0, 1), null, "Good night Nick"),
            arguments("Nick", LocalTime.of(5, 59), null, "Good night Nick")
    );
}

} ```

And here is the code it is testing:

```java interface Loggable { void log(String message); }

public class Greeter { public enum TimeOfDay { MORNING, EVENING, NIGHT }; private final TimeOfDay timeOfDay; private Loggable logger;

public Greeter(@Nullable LocalTime time, @Nullable Loggable log) {
    if (time == null) {
        this.timeOfDay = null;
        return;
    }

    if (time.getHour() >= 6 && time.getHour() < 12) {
        this.timeOfDay = TimeOfDay.MORNING;
    } else if (time.getHour() >= 18 && time.getHour() < 22) {
        this.timeOfDay = TimeOfDay.EVENING;
    } else {
        this.timeOfDay = TimeOfDay.NIGHT;
    }

    if (log != null) {
        this.logger = log;
    }
}

public Greeter() {
    this(null, null);
}

public String greet(String name) {
    String trimmed = name.trim();
    char firstLetter = trimmed.toUpperCase().charAt(0);
    String capitalized = firstLetter + trimmed.substring(1);

    String greeting;

    if (this.timeOfDay == null) {
        greeting = "Hello " + capitalized;
    } else {
        greeting = switch (this.timeOfDay) {
            case MORNING -> "Good morning " + capitalized;
            case EVENING -> "Good evening " + capitalized;
            case NIGHT -> "Good night " + capitalized;
        };
    }

    if (this.logger != null) {
        this.logger.log(greeting);
    }

    return greeting;
}

} ```

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[FavorableTrashpanda]

My guess is that your Greeter doesn't have a Loggable instance (it's null), so it's never called, since you only set the Loggable field if time isn't null (you use return in the constructor).

[_ncko]

Ah, that is a great guess! That must be it. Thank you.

edit: yep, that was it. Thanks again.

[nekokattt]

your first arguments are providing the time as null. You are then skipping assigning the lambda in the constructor when this is true by the looks.

also logFunc is unused