How to ignore a lambda when comparing for equality?

Given this class:

data class MyClass(
    val foo: String,
    val bar: () -> Unit
)

I want to assert that two instances of MyClass are equal, ignoring the lambda field bar. How do I make this work with Mockito?

Here's the code that doesn't work:

        val actual = MyClass("foo", bar = {})
        val expected = MyClass("foo", bar = Mockito.any())

        assertEquals(expected, actual)

Solution

Without changing the Class:

You could create the expected by copying the actual field. For example:
```
val expected = actual.copy(foo = "foo")
```
If the object is instantiated elsewhere, then you could create a copy of the actual field. For example:
```
assertEquals(expected, actual.copy(bar = expected.bar)
```

Changing the Class:

Only fields inside the primary constructor are taken into account when building the equals method. You could remove the bar field from the primary constructor. For example:
```
data class MyClass(
    val foo: String
) {
    val bar: () -> Unit = {}
}
```

You could override the equals method in the class. For example:

data class MyClass(
    val foo: String,
    val bar: () -> Unit
) {
    override fun equals(other: Any?): Boolean {
        return (other as? MyClass)?.foo == foo
    }

    override fun hashCode(): Int {
        return foo.hashCode()
    }
}