Powermock: How to mock a method in an enumeration constant
I have an enumeration type which I used as a collection of factories for other objects that implement a common interface. A simplified version of the code is:
interface Operation {
void execute();
}
enum Factory {
TYPE1(Class1::new),
TYPE2(Class2::new);
private Supplier<Operation> constructor;
Factory(Supplier<Operation> constructor) {
this.constructor = constructor;
}
Operation build() {
return constructor.get();
}
}
A simplified version of the client code looks like:
class Client {
private void run(EnumSet<Factory> required) {
for (Factory x : required) {
x.build().execute();
}
}
// Some code that calls run() with the right EnumSet
}
This all appears to work as expected, so I want to write some Unit tests.
Testing the Factory is easy, but the Client is proving more difficult. The problem is that I don't want to start calling the Operation (they do a lot of work). Instead I'd like to get x.build() return a mock object.
I've tried using PowerMocks whenNew to trap the creation of the Operation objects, but this doesn't work (I don't actually have any 'new' operations). I've also tried to use a Powermock 'spy', but this fails because the enumeration constants are real objects.
Any ideas?
java unit-testing mocking powermock powermockito
asked Nov 13 at 14:51
Stormcloud
9941925
add a comment |
I have an enumeration type which I used as a collection of factories for other objects that implement a common interface. A simplified version of the code is:
interface Operation {
void execute();
}
enum Factory {
TYPE1(Class1::new),
TYPE2(Class2::new);
private Supplier<Operation> constructor;
Factory(Supplier<Operation> constructor) {
this.constructor = constructor;
}
Operation build() {
return constructor.get();
}
}
A simplified version of the client code looks like:
class Client {
private void run(EnumSet<Factory> required) {
for (Factory x : required) {
x.build().execute();
}
}
// Some code that calls run() with the right EnumSet
}
This all appears to work as expected, so I want to write some Unit tests.
Testing the Factory is easy, but the Client is proving more difficult. The problem is that I don't want to start calling the Operation (they do a lot of work). Instead I'd like to get x.build() return a mock object.
I've tried using PowerMocks whenNew to trap the creation of the Operation objects, but this doesn't work (I don't actually have any 'new' operations). I've also tried to use a Powermock 'spy', but this fails because the enumeration constants are real objects.
Any ideas?
java unit-testing mocking powermock powermockito
asked Nov 13 at 14:51
Stormcloud
9941925
Any feedback on my answer? If you found it helpful, pls dont forget about accepting, otherwise let me know if I can add anything to it ...
– GhostCat
Nov 15 at 15:50
Hi, I've been playing with the Powermock solution over the last couple of days, but I've not been able to get it to work :-( In the linked question the enumeration contained an abstract method which is why (I think) the individual constants have their own class. In this case there are no abstract methods, so the compiler only produces a single class file.
– Stormcloud
Nov 16 at 11:15
I see. But as said: I consider PowerMock(ito) to always be the last straw. If possible, change your production code, and make it easier to test. Anything else is using black magic to circumvent a designed-in deficiency.
– GhostCat
Nov 16 at 11:30
For the moment my work around is to add a setter function to the enumeration constants so thatbuild()can return prebuilt objects - my mocks. While it means I've only made a small change to the production code it does mean that my enumeration 'constant' is now mutable! This feels worse then the alternatives.
– Stormcloud
Nov 16 at 11:58
add a comment |
I have an enumeration type which I used as a collection of factories for other objects that implement a common interface. A simplified version of the code is:
interface Operation {
void execute();
}
enum Factory {
TYPE1(Class1::new),
TYPE2(Class2::new);
private Supplier<Operation> constructor;
Factory(Supplier<Operation> constructor) {
this.constructor = constructor;
}
Operation build() {
return constructor.get();
}
}
A simplified version of the client code looks like:
class Client {
private void run(EnumSet<Factory> required) {
for (Factory x : required) {
x.build().execute();
}
}
// Some code that calls run() with the right EnumSet
}
This all appears to work as expected, so I want to write some Unit tests.
Testing the Factory is easy, but the Client is proving more difficult. The problem is that I don't want to start calling the Operation (they do a lot of work). Instead I'd like to get x.build() return a mock object.
I've tried using PowerMocks whenNew to trap the creation of the Operation objects, but this doesn't work (I don't actually have any 'new' operations). I've also tried to use a Powermock 'spy', but this fails because the enumeration constants are real objects.
Any ideas?
java unit-testing mocking powermock powermockito
asked Nov 13 at 14:51
Stormcloud
9941925
I have an enumeration type which I used as a collection of factories for other objects that implement a common interface. A simplified version of the code is:
interface Operation {
void execute();
}
enum Factory {
TYPE1(Class1::new),
TYPE2(Class2::new);
private Supplier<Operation> constructor;
Factory(Supplier<Operation> constructor) {
this.constructor = constructor;
}
Operation build() {
return constructor.get();
}
}
A simplified version of the client code looks like:
class Client {
private void run(EnumSet<Factory> required) {
for (Factory x : required) {
x.build().execute();
}
}
// Some code that calls run() with the right EnumSet
}
This all appears to work as expected, so I want to write some Unit tests.
Testing the Factory is easy, but the Client is proving more difficult. The problem is that I don't want to start calling the Operation (they do a lot of work). Instead I'd like to get x.build() return a mock object.
I've tried using PowerMocks whenNew to trap the creation of the Operation objects, but this doesn't work (I don't actually have any 'new' operations). I've also tried to use a Powermock 'spy', but this fails because the enumeration constants are real objects.
Any ideas?
java unit-testing mocking powermock powermockito
java unit-testing mocking powermock powermockito
asked Nov 13 at 14:51
Stormcloud
9941925
asked Nov 13 at 14:51
Stormcloud
9941925
asked Nov 13 at 14:51
Stormcloud
9941925
asked Nov 13 at 14:51
Stormcloud
9941925
asked Nov 13 at 14:51
Stormcloud
9941925
9941925
Any feedback on my answer? If you found it helpful, pls dont forget about accepting, otherwise let me know if I can add anything to it ...
– GhostCat
Nov 15 at 15:50
Hi, I've been playing with the Powermock solution over the last couple of days, but I've not been able to get it to work :-( In the linked question the enumeration contained an abstract method which is why (I think) the individual constants have their own class. In this case there are no abstract methods, so the compiler only produces a single class file.
– Stormcloud
Nov 16 at 11:15
I see. But as said: I consider PowerMock(ito) to always be the last straw. If possible, change your production code, and make it easier to test. Anything else is using black magic to circumvent a designed-in deficiency.
– GhostCat
Nov 16 at 11:30
For the moment my work around is to add a setter function to the enumeration constants so thatbuild()can return prebuilt objects - my mocks. While it means I've only made a small change to the production code it does mean that my enumeration 'constant' is now mutable! This feels worse then the alternatives.
– Stormcloud
Nov 16 at 11:58
add a comment |
Any feedback on my answer? If you found it helpful, pls dont forget about accepting, otherwise let me know if I can add anything to it ...
– GhostCat
Nov 15 at 15:50
Hi, I've been playing with the Powermock solution over the last couple of days, but I've not been able to get it to work :-( In the linked question the enumeration contained an abstract method which is why (I think) the individual constants have their own class. In this case there are no abstract methods, so the compiler only produces a single class file.
– Stormcloud
Nov 16 at 11:15
I see. But as said: I consider PowerMock(ito) to always be the last straw. If possible, change your production code, and make it easier to test. Anything else is using black magic to circumvent a designed-in deficiency.
– GhostCat
Nov 16 at 11:30
For the moment my work around is to add a setter function to the enumeration constants so thatbuild()can return prebuilt objects - my mocks. While it means I've only made a small change to the production code it does mean that my enumeration 'constant' is now mutable! This feels worse then the alternatives.
– Stormcloud
Nov 16 at 11:58
Any feedback on my answer? If you found it helpful, pls dont forget about accepting, otherwise let me know if I can add anything to it ...
– GhostCat
Nov 15 at 15:50
Any feedback on my answer? If you found it helpful, pls dont forget about accepting, otherwise let me know if I can add anything to it ...
– GhostCat
Nov 15 at 15:50
Hi, I've been playing with the Powermock solution over the last couple of days, but I've not been able to get it to work :-( In the linked question the enumeration contained an abstract method which is why (I think) the individual constants have their own class. In this case there are no abstract methods, so the compiler only produces a single class file.
– Stormcloud
Nov 16 at 11:15
Hi, I've been playing with the Powermock solution over the last couple of days, but I've not been able to get it to work :-( In the linked question the enumeration contained an abstract method which is why (I think) the individual constants have their own class. In this case there are no abstract methods, so the compiler only produces a single class file.
– Stormcloud
Nov 16 at 11:15
I see. But as said: I consider PowerMock(ito) to always be the last straw. If possible, change your production code, and make it easier to test. Anything else is using black magic to circumvent a designed-in deficiency.
– GhostCat
Nov 16 at 11:30
I see. But as said: I consider PowerMock(ito) to always be the last straw. If possible, change your production code, and make it easier to test. Anything else is using black magic to circumvent a designed-in deficiency.
– GhostCat
Nov 16 at 11:30
For the moment my work around is to add a setter function to the enumeration constants so that
build() can return prebuilt objects - my mocks. While it means I've only made a small change to the production code it does mean that my enumeration 'constant' is now mutable! This feels worse then the alternatives.– Stormcloud
Nov 16 at 11:58
For the moment my work around is to add a setter function to the enumeration constants so that
build() can return prebuilt objects - my mocks. While it means I've only made a small change to the production code it does mean that my enumeration 'constant' is now mutable! This feels worse then the alternatives.– Stormcloud
Nov 16 at 11:58
add a comment |
1 Answer
1
active
oldest
votes
Two solutions:
- you insist on using PowerMock(ito). Then the simple issue is: you are probably preparing the wrong class for test. You have to temper with those enum constants, and they are inner classes. But it is possible, see this answer for example.
- you step back, and improve your production code, to make it easier to test.
For example like this:
interface OperationProvider {
Operation build();
}
to be used like:
enum Factory implements OperationProvider {
And now you can change your client code to do
OperationProvider ourProvider = ...
whatever.build();...
The point is: when using dependency injection, you simply pass a mocked OperationProvider. This means that you can basically sidestep the need to mock with your enum completely. You just have to make sure that within your production code, you obviously pass one of the enum constants when initializing that ourProvider field for example.
answered Nov 14 at 9:11
GhostCat
88.1k1684144
add a comment |
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1 Answer
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oldest
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oldest
votes
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oldest
votes
Two solutions:
- you insist on using PowerMock(ito). Then the simple issue is: you are probably preparing the wrong class for test. You have to temper with those enum constants, and they are inner classes. But it is possible, see this answer for example.
- you step back, and improve your production code, to make it easier to test.
For example like this:
interface OperationProvider {
Operation build();
}
to be used like:
enum Factory implements OperationProvider {
And now you can change your client code to do
OperationProvider ourProvider = ...
whatever.build();...
The point is: when using dependency injection, you simply pass a mocked OperationProvider. This means that you can basically sidestep the need to mock with your enum completely. You just have to make sure that within your production code, you obviously pass one of the enum constants when initializing that ourProvider field for example.
answered Nov 14 at 9:11
GhostCat
88.1k1684144
add a comment |
Two solutions:
- you insist on using PowerMock(ito). Then the simple issue is: you are probably preparing the wrong class for test. You have to temper with those enum constants, and they are inner classes. But it is possible, see this answer for example.
- you step back, and improve your production code, to make it easier to test.
For example like this:
interface OperationProvider {
Operation build();
}
to be used like:
enum Factory implements OperationProvider {
And now you can change your client code to do
OperationProvider ourProvider = ...
whatever.build();...
The point is: when using dependency injection, you simply pass a mocked OperationProvider. This means that you can basically sidestep the need to mock with your enum completely. You just have to make sure that within your production code, you obviously pass one of the enum constants when initializing that ourProvider field for example.
answered Nov 14 at 9:11
GhostCat
88.1k1684144
add a comment |
Two solutions:
- you insist on using PowerMock(ito). Then the simple issue is: you are probably preparing the wrong class for test. You have to temper with those enum constants, and they are inner classes. But it is possible, see this answer for example.
- you step back, and improve your production code, to make it easier to test.
For example like this:
interface OperationProvider {
Operation build();
}
to be used like:
enum Factory implements OperationProvider {
And now you can change your client code to do
OperationProvider ourProvider = ...
whatever.build();...
The point is: when using dependency injection, you simply pass a mocked OperationProvider. This means that you can basically sidestep the need to mock with your enum completely. You just have to make sure that within your production code, you obviously pass one of the enum constants when initializing that ourProvider field for example.
answered Nov 14 at 9:11
GhostCat
88.1k1684144
Two solutions:
- you insist on using PowerMock(ito). Then the simple issue is: you are probably preparing the wrong class for test. You have to temper with those enum constants, and they are inner classes. But it is possible, see this answer for example.
- you step back, and improve your production code, to make it easier to test.
For example like this:
interface OperationProvider {
Operation build();
}
to be used like:
enum Factory implements OperationProvider {
And now you can change your client code to do
OperationProvider ourProvider = ...
whatever.build();...
The point is: when using dependency injection, you simply pass a mocked OperationProvider. This means that you can basically sidestep the need to mock with your enum completely. You just have to make sure that within your production code, you obviously pass one of the enum constants when initializing that ourProvider field for example.
answered Nov 14 at 9:11
GhostCat
88.1k1684144
answered Nov 14 at 9:11
GhostCat
88.1k1684144
answered Nov 14 at 9:11
GhostCat
88.1k1684144
answered Nov 14 at 9:11
GhostCat
88.1k1684144
88.1k1684144
add a comment |
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Any feedback on my answer? If you found it helpful, pls dont forget about accepting, otherwise let me know if I can add anything to it ...
– GhostCat
Nov 15 at 15:50
Hi, I've been playing with the Powermock solution over the last couple of days, but I've not been able to get it to work :-( In the linked question the enumeration contained an abstract method which is why (I think) the individual constants have their own class. In this case there are no abstract methods, so the compiler only produces a single class file.
– Stormcloud
Nov 16 at 11:15
I see. But as said: I consider PowerMock(ito) to always be the last straw. If possible, change your production code, and make it easier to test. Anything else is using black magic to circumvent a designed-in deficiency.
– GhostCat
Nov 16 at 11:30
For the moment my work around is to add a setter function to the enumeration constants so that
build()can return prebuilt objects - my mocks. While it means I've only made a small change to the production code it does mean that my enumeration 'constant' is now mutable! This feels worse then the alternatives.– Stormcloud
Nov 16 at 11:58