Mockito - how to mock, and express expectations, on an abstract method of a class (i.e. a callback)
I'm trying to unit-test an abstract class, therefore need to provide a mock implementation to the class' abstract methods.
I think I'm in a niche situation (!) since neither @Mock or @Spy seem to help.
- tried
Mockito.mock(SimpleClient.class, Mockito.CALLS_REAL_METHODS)but this totally shatters my abstract class (creates it without calling the constructor, running into NPE) - tried
@Spybut this either requires an instance of the real class (which I cannot provide since it's abstract duh), or, it will attempt to call a no-arg constructor which doesn't exist.
(Context, although you should not need it: the class is a messaging client e.g. has sendMessage() and abstract onMessage() methods, and obviously I need to use the real implementation of sendMessage() and mock the callback abstract onMessage())
java mocking mockito abstract spy
asked Nov 25 '18 at 13:06
haelixhaelix
1,61832034
add a comment |
I'm trying to unit-test an abstract class, therefore need to provide a mock implementation to the class' abstract methods.
I think I'm in a niche situation (!) since neither @Mock or @Spy seem to help.
- tried
Mockito.mock(SimpleClient.class, Mockito.CALLS_REAL_METHODS)but this totally shatters my abstract class (creates it without calling the constructor, running into NPE) - tried
@Spybut this either requires an instance of the real class (which I cannot provide since it's abstract duh), or, it will attempt to call a no-arg constructor which doesn't exist.
(Context, although you should not need it: the class is a messaging client e.g. has sendMessage() and abstract onMessage() methods, and obviously I need to use the real implementation of sendMessage() and mock the callback abstract onMessage())
java mocking mockito abstract spy
asked Nov 25 '18 at 13:06
haelixhaelix
1,61832034
Is there a reason you cannot provide a dummy implementation instead? For example,sendMessagesimply puts your message on a list which the test can read?
– Joe C
Nov 25 '18 at 13:08
@JoeC yes, the reason is, I have in fact 12 callbacks and I feel ridiculous to provide dummies and continue to use Mockito despite not being able to help in such a basic, commonplace scenario
– haelix
Nov 25 '18 at 13:10
add a comment |
I'm trying to unit-test an abstract class, therefore need to provide a mock implementation to the class' abstract methods.
I think I'm in a niche situation (!) since neither @Mock or @Spy seem to help.
- tried
Mockito.mock(SimpleClient.class, Mockito.CALLS_REAL_METHODS)but this totally shatters my abstract class (creates it without calling the constructor, running into NPE) - tried
@Spybut this either requires an instance of the real class (which I cannot provide since it's abstract duh), or, it will attempt to call a no-arg constructor which doesn't exist.
(Context, although you should not need it: the class is a messaging client e.g. has sendMessage() and abstract onMessage() methods, and obviously I need to use the real implementation of sendMessage() and mock the callback abstract onMessage())
java mocking mockito abstract spy
asked Nov 25 '18 at 13:06
haelixhaelix
1,61832034
I'm trying to unit-test an abstract class, therefore need to provide a mock implementation to the class' abstract methods.
I think I'm in a niche situation (!) since neither @Mock or @Spy seem to help.
- tried
Mockito.mock(SimpleClient.class, Mockito.CALLS_REAL_METHODS)but this totally shatters my abstract class (creates it without calling the constructor, running into NPE) - tried
@Spybut this either requires an instance of the real class (which I cannot provide since it's abstract duh), or, it will attempt to call a no-arg constructor which doesn't exist.
(Context, although you should not need it: the class is a messaging client e.g. has sendMessage() and abstract onMessage() methods, and obviously I need to use the real implementation of sendMessage() and mock the callback abstract onMessage())
java mocking mockito abstract spy
java mocking mockito abstract spy
asked Nov 25 '18 at 13:06
haelixhaelix
1,61832034
asked Nov 25 '18 at 13:06
haelixhaelix
1,61832034
asked Nov 25 '18 at 13:06
haelixhaelix
1,61832034
asked Nov 25 '18 at 13:06
haelixhaelix
1,61832034
asked Nov 25 '18 at 13:06
haelixhaelix
1,61832034
1,61832034
Is there a reason you cannot provide a dummy implementation instead? For example,sendMessagesimply puts your message on a list which the test can read?
– Joe C
Nov 25 '18 at 13:08
@JoeC yes, the reason is, I have in fact 12 callbacks and I feel ridiculous to provide dummies and continue to use Mockito despite not being able to help in such a basic, commonplace scenario
– haelix
Nov 25 '18 at 13:10
add a comment |
Is there a reason you cannot provide a dummy implementation instead? For example,sendMessagesimply puts your message on a list which the test can read?
– Joe C
Nov 25 '18 at 13:08
@JoeC yes, the reason is, I have in fact 12 callbacks and I feel ridiculous to provide dummies and continue to use Mockito despite not being able to help in such a basic, commonplace scenario
– haelix
Nov 25 '18 at 13:10
Is there a reason you cannot provide a dummy implementation instead? For example,
sendMessage simply puts your message on a list which the test can read?– Joe C
Nov 25 '18 at 13:08
Is there a reason you cannot provide a dummy implementation instead? For example,
sendMessage simply puts your message on a list which the test can read?– Joe C
Nov 25 '18 at 13:08
@JoeC yes, the reason is, I have in fact 12 callbacks and I feel ridiculous to provide dummies and continue to use Mockito despite not being able to help in such a basic, commonplace scenario
– haelix
Nov 25 '18 at 13:10
@JoeC yes, the reason is, I have in fact 12 callbacks and I feel ridiculous to provide dummies and continue to use Mockito despite not being able to help in such a basic, commonplace scenario
– haelix
Nov 25 '18 at 13:10
add a comment |
1 Answer
1
active
oldest
votes
I found the following
to go the first approach (
Mockito.mock), they have added the ability to construct an underlying real object properly using an arbitrary constructor (And hopefully after that, Moquito goes on to "stub" each method as you express expectations on it, like the below):
MyClass mock = Mockito.mock(MyClass.class, Mockito.withSettings()
.useConstructor("stringArg", 17)
.defaultAnswer(Mockito.CALLS_REAL_METHODS));
// ...
Mockito.when(mock.onMyAbstractMethod(Mockito.anyInt())).then(
invocation -> mock.callAnotherRealMethodOnTheMock(invocation.getArgument(0)));
to go the second approach indeed a
@Spyneeds a created instance of the class, so in that case you really need to subclass it first.
Extra note: a separate issue, ugly as well, happens if say onMyAbstractMethod returns void, in that case the Mockito.when... syntax doesn't work due to a language limitation it seems, a fact which is poorly documented. One needs to do it the other way around and say:
Mockito.doAnswer(invocation -> mock.callAnotherRealMethodOnTheMock(invocation.getArgument(0)))
.when(mock).onMyAbstractMethod(1);
answered Nov 25 '18 at 22:31
haelixhaelix
1,61832034
add a comment |
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
I found the following
to go the first approach (
Mockito.mock), they have added the ability to construct an underlying real object properly using an arbitrary constructor (And hopefully after that, Moquito goes on to "stub" each method as you express expectations on it, like the below):
MyClass mock = Mockito.mock(MyClass.class, Mockito.withSettings()
.useConstructor("stringArg", 17)
.defaultAnswer(Mockito.CALLS_REAL_METHODS));
// ...
Mockito.when(mock.onMyAbstractMethod(Mockito.anyInt())).then(
invocation -> mock.callAnotherRealMethodOnTheMock(invocation.getArgument(0)));
to go the second approach indeed a
@Spyneeds a created instance of the class, so in that case you really need to subclass it first.
Extra note: a separate issue, ugly as well, happens if say onMyAbstractMethod returns void, in that case the Mockito.when... syntax doesn't work due to a language limitation it seems, a fact which is poorly documented. One needs to do it the other way around and say:
Mockito.doAnswer(invocation -> mock.callAnotherRealMethodOnTheMock(invocation.getArgument(0)))
.when(mock).onMyAbstractMethod(1);
answered Nov 25 '18 at 22:31
haelixhaelix
1,61832034
add a comment |
I found the following
to go the first approach (
Mockito.mock), they have added the ability to construct an underlying real object properly using an arbitrary constructor (And hopefully after that, Moquito goes on to "stub" each method as you express expectations on it, like the below):
MyClass mock = Mockito.mock(MyClass.class, Mockito.withSettings()
.useConstructor("stringArg", 17)
.defaultAnswer(Mockito.CALLS_REAL_METHODS));
// ...
Mockito.when(mock.onMyAbstractMethod(Mockito.anyInt())).then(
invocation -> mock.callAnotherRealMethodOnTheMock(invocation.getArgument(0)));
to go the second approach indeed a
@Spyneeds a created instance of the class, so in that case you really need to subclass it first.
Extra note: a separate issue, ugly as well, happens if say onMyAbstractMethod returns void, in that case the Mockito.when... syntax doesn't work due to a language limitation it seems, a fact which is poorly documented. One needs to do it the other way around and say:
Mockito.doAnswer(invocation -> mock.callAnotherRealMethodOnTheMock(invocation.getArgument(0)))
.when(mock).onMyAbstractMethod(1);
answered Nov 25 '18 at 22:31
haelixhaelix
1,61832034
add a comment |
I found the following
to go the first approach (
Mockito.mock), they have added the ability to construct an underlying real object properly using an arbitrary constructor (And hopefully after that, Moquito goes on to "stub" each method as you express expectations on it, like the below):
MyClass mock = Mockito.mock(MyClass.class, Mockito.withSettings()
.useConstructor("stringArg", 17)
.defaultAnswer(Mockito.CALLS_REAL_METHODS));
// ...
Mockito.when(mock.onMyAbstractMethod(Mockito.anyInt())).then(
invocation -> mock.callAnotherRealMethodOnTheMock(invocation.getArgument(0)));
to go the second approach indeed a
@Spyneeds a created instance of the class, so in that case you really need to subclass it first.
Extra note: a separate issue, ugly as well, happens if say onMyAbstractMethod returns void, in that case the Mockito.when... syntax doesn't work due to a language limitation it seems, a fact which is poorly documented. One needs to do it the other way around and say:
Mockito.doAnswer(invocation -> mock.callAnotherRealMethodOnTheMock(invocation.getArgument(0)))
.when(mock).onMyAbstractMethod(1);
answered Nov 25 '18 at 22:31
haelixhaelix
1,61832034
I found the following
to go the first approach (
Mockito.mock), they have added the ability to construct an underlying real object properly using an arbitrary constructor (And hopefully after that, Moquito goes on to "stub" each method as you express expectations on it, like the below):
MyClass mock = Mockito.mock(MyClass.class, Mockito.withSettings()
.useConstructor("stringArg", 17)
.defaultAnswer(Mockito.CALLS_REAL_METHODS));
// ...
Mockito.when(mock.onMyAbstractMethod(Mockito.anyInt())).then(
invocation -> mock.callAnotherRealMethodOnTheMock(invocation.getArgument(0)));
to go the second approach indeed a
@Spyneeds a created instance of the class, so in that case you really need to subclass it first.
Extra note: a separate issue, ugly as well, happens if say onMyAbstractMethod returns void, in that case the Mockito.when... syntax doesn't work due to a language limitation it seems, a fact which is poorly documented. One needs to do it the other way around and say:
Mockito.doAnswer(invocation -> mock.callAnotherRealMethodOnTheMock(invocation.getArgument(0)))
.when(mock).onMyAbstractMethod(1);
answered Nov 25 '18 at 22:31
haelixhaelix
1,61832034
answered Nov 25 '18 at 22:31
haelixhaelix
1,61832034
answered Nov 25 '18 at 22:31
haelixhaelix
1,61832034
answered Nov 25 '18 at 22:31
haelixhaelix
1,61832034
1,61832034
add a comment |
add a comment |
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Is there a reason you cannot provide a dummy implementation instead? For example,
sendMessagesimply puts your message on a list which the test can read?– Joe C
Nov 25 '18 at 13:08
@JoeC yes, the reason is, I have in fact 12 callbacks and I feel ridiculous to provide dummies and continue to use Mockito despite not being able to help in such a basic, commonplace scenario
– haelix
Nov 25 '18 at 13:10