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Agreed. If I use an LLM to generate fairly exhaustive unit tests of a trivial function just because I can, that doesn’t mean those lines are as useful as core

Agreed. If I use an LLM to generate fairly exhaustive unit tests of a trivial function just because I can, that doesn’t mean those lines are as useful as core complex business logic that it would almost certainly make subtle mistakes in.

andsoitis 1y ago
> If I … generate fairly exhaustive unit tests of a trivial function … then you are not a senior software engineer
- triyambakam 1y ago
  Neither are you if that's your understanding of a senior engineer
  - mgh95 1y ago
    I think the parent commentors point was that it is nearly trivial to generate variations on unit tests in most (if not all) unit test frameworks. For example: Java: https://docs.parasoft.com/display/JTEST20232/Creating+a+Parameterized+Unit+Test https://docs.parasoft.com/display/JTEST20232/Creating+a+Para... C# (nunit, but xunit has this too): https://docs.nunit.org/articles/nunit/technical-notes/usage/Parameterized-Tests.html https://docs.nunit.org/articles/nunit/technical-notes/usage/... Python: https://docs.pytest.org/en/stable/example/parametrize.html https://docs.pytest.org/en/stable/example/parametrize.html cpp: https://google.github.io/googletest/advanced.html https://google.github.io/googletest/advanced.html A belief that the ability of LLMs to generate parameterizations is intrinsically helpful to a degree which cannot be trivially achieved in most mainstream programming languages/test frameworks may be an indicator that an individual has not achieved a substantial depth of experience.
    - com2kid 1y ago
      The useful part is generating the mocks. The various auto mocking frameworks are so hit or miss I end up having to manually make mocks which is time consuming and boring. LLMs help out dramatically and save literally hours of boring error prone work.
      - mgh95 1y ago
        Why mock at all? Spend the time making integration tests fast. There is little reason a database, queue, etc. can't be set up in a per-test group basis and be made fast. Reliable software is built upon (mostly) reliable foundations.
        lanstin 1y ago
        hmmmm. I do like integration tests, but I often tell people the art of modern software is to make reliable systems on top of unreliable components. And the integration tests should 100% include times when the network flakes out and drops 1/2 of replies and corrupts msgs and the like.
        mgh95 1y ago
        > I do like integration tests, but I often tell people the art of modern software is to make reliable systems on top of unreliable components. There is a dramatic difference between unreliable in the sense of S3 or other services and unreliable as in "we get different sets of logical outputs when we provide the same input to a LLM". In the first, you can prepare for what are logical outcomes -- network failures, durability loss, etc. In the latter, unless you know the total space of outputs for a LLM you cannot prepare. In the operational sense, LLMs are not a system component, they are a system builder. And a rather poor one, at that. > And the integration tests should 100% include times when the network flakes out and drops 1/2 of replies and corrupts msgs and the like. Yeah, it's not that hard to include that in modern testing.
        sethammons 1y ago
        Minor nit. I wouldn't call those failing systems tests integration tests. Unit tests are for validation of error paths. Unit tests can leverage mocks or fakes. Need 3 retires with exponential back off, use unit tests and fakes. Integration tests should use real components. Typically, integration tests are happy path and unit are error paths. Making real components fail and having tests validate failure handling in a more complete environment jumps from integration testing to resilience or chaos testing. Being able to accurately validate backoffs and retries may diminish, but validating intermediate or ending state can be done with artifact monitoring via sinks. There is unit-integration testing which fakes out as little as possible but still fakes out some edges. The difference being that the failures are introduced via fake vs managing actual system components. If you connect to a real db on unit-integration tests, you typically wouldn't kill the db or use Comcast to slow the network artificially. That would be reserved for the next layer in the test pyramid.
    - VectorLock 1y ago
      Parameterized tests are good, but I think he might be talking about exercising all the corner cases in the logic of your function, which to my knowledge almost no languages can auto-generate for but LLMs can sorta-ish figure it out.
      - mgh95 1y ago
        We are talking about basic computing for CRUD apps. When you start needing to rely upon "sorta-ish" to describe the efficacy or a tool for such a straightforward and deterministic use case, it may be an indicator you need to rethink your approach.
        VectorLock 1y ago
        If you want to discount a tool that may save you an immense amount of time because you might have to help it along the fast few feet, thats up to you. If you can share a tool that can analyze a function and create a test for all corner cases in a popular language, I'm sure some people would be interested in that.
        mgh95 1y ago
        You should look up intellitest and reshaper test generator. Products exist for this.
        imtringued 1y ago
        Maybe you should have brought that up earlier instead of acting smug and burying the lede? It's also pretty telling that you didn't elaborate this further and kept your comment short. What you should have said is that some parameterized test generators do automated white box testing where they look at your code similar to a fuzzer and try to find the test cases automatically. Your first link is literally just setting up an array with test cases, which basically means you'd have to use an LLM to quickly produce the test cases anyway, which makes parameterized testing sound exceedingly pathetic. https://learn.microsoft.com/en-us/visualstudio/test/generate-unit-tests-for-your-code-with-intellitest?view=vs-2022 https://learn.microsoft.com/en-us/visualstudio/test/generate... >IntelliTest explores your .NET code to generate test data and a suite of unit tests. For every statement in the code, a test input is generated that will execute that statement. A case analysis is performed for every conditional branch in the code. For example, if statements, assertions, and all operations that can throw exceptions are analyzed. This analysis is used to generate test data for a parameterized unit test for each of your methods, creating unit tests with high code coverage. Think of it as smart fuzz testing that trims down the inputs and test cases to what executes all your logic branches and checks for exceptions.
    - imtringued 1y ago
      99% of the work in testing is coming up with test scenarios and test cases. 95% of the code is just dealing with setting up input and output data, 4% is calling the code you want to test and the final assert is often just a single line of code. I'm not sure what depth of experience has to do with any of this, since it is busy work that costs a lot of time. A form with 120 fields is a form with 120 fields. There is no way around coming up with the several dozens of test cases that you're going to test without filling out almost all of the fields, even the ones that are not relevant to the test itself, otherwise you're not really testing your application.
  - goosejuice 1y ago
    We're not a licensed profession with universally defined roles. It's whatever the speaker wants it to be given how wildly it varies.

andsoitis 1y ago

> If I … generate fairly exhaustive unit tests of a trivial function … then you are not a senior software engineer

triyambakam 1y ago
Neither are you if that's your understanding of a senior engineer
- mgh95 1y ago
  I think the parent commentors point was that it is nearly trivial to generate variations on unit tests in most (if not all) unit test frameworks. For example: Java: https://docs.parasoft.com/display/JTEST20232/Creating+a+Parameterized+Unit+Test https://docs.parasoft.com/display/JTEST20232/Creating+a+Para... C# (nunit, but xunit has this too): https://docs.nunit.org/articles/nunit/technical-notes/usage/Parameterized-Tests.html https://docs.nunit.org/articles/nunit/technical-notes/usage/... Python: https://docs.pytest.org/en/stable/example/parametrize.html https://docs.pytest.org/en/stable/example/parametrize.html cpp: https://google.github.io/googletest/advanced.html https://google.github.io/googletest/advanced.html A belief that the ability of LLMs to generate parameterizations is intrinsically helpful to a degree which cannot be trivially achieved in most mainstream programming languages/test frameworks may be an indicator that an individual has not achieved a substantial depth of experience.
  - com2kid 1y ago
    The useful part is generating the mocks. The various auto mocking frameworks are so hit or miss I end up having to manually make mocks which is time consuming and boring. LLMs help out dramatically and save literally hours of boring error prone work.
    - mgh95 1y ago
      Why mock at all? Spend the time making integration tests fast. There is little reason a database, queue, etc. can't be set up in a per-test group basis and be made fast. Reliable software is built upon (mostly) reliable foundations.
      - lanstin 1y ago
        hmmmm. I do like integration tests, but I often tell people the art of modern software is to make reliable systems on top of unreliable components. And the integration tests should 100% include times when the network flakes out and drops 1/2 of replies and corrupts msgs and the like.
        mgh95 1y ago
        > I do like integration tests, but I often tell people the art of modern software is to make reliable systems on top of unreliable components. There is a dramatic difference between unreliable in the sense of S3 or other services and unreliable as in "we get different sets of logical outputs when we provide the same input to a LLM". In the first, you can prepare for what are logical outcomes -- network failures, durability loss, etc. In the latter, unless you know the total space of outputs for a LLM you cannot prepare. In the operational sense, LLMs are not a system component, they are a system builder. And a rather poor one, at that. > And the integration tests should 100% include times when the network flakes out and drops 1/2 of replies and corrupts msgs and the like. Yeah, it's not that hard to include that in modern testing.
        sethammons 1y ago
        Minor nit. I wouldn't call those failing systems tests integration tests. Unit tests are for validation of error paths. Unit tests can leverage mocks or fakes. Need 3 retires with exponential back off, use unit tests and fakes. Integration tests should use real components. Typically, integration tests are happy path and unit are error paths. Making real components fail and having tests validate failure handling in a more complete environment jumps from integration testing to resilience or chaos testing. Being able to accurately validate backoffs and retries may diminish, but validating intermediate or ending state can be done with artifact monitoring via sinks. There is unit-integration testing which fakes out as little as possible but still fakes out some edges. The difference being that the failures are introduced via fake vs managing actual system components. If you connect to a real db on unit-integration tests, you typically wouldn't kill the db or use Comcast to slow the network artificially. That would be reserved for the next layer in the test pyramid.
  - VectorLock 1y ago
    Parameterized tests are good, but I think he might be talking about exercising all the corner cases in the logic of your function, which to my knowledge almost no languages can auto-generate for but LLMs can sorta-ish figure it out.
    - mgh95 1y ago
      We are talking about basic computing for CRUD apps. When you start needing to rely upon "sorta-ish" to describe the efficacy or a tool for such a straightforward and deterministic use case, it may be an indicator you need to rethink your approach.
      - VectorLock 1y ago
        If you want to discount a tool that may save you an immense amount of time because you might have to help it along the fast few feet, thats up to you. If you can share a tool that can analyze a function and create a test for all corner cases in a popular language, I'm sure some people would be interested in that.
        mgh95 1y ago
        You should look up intellitest and reshaper test generator. Products exist for this.
        imtringued 1y ago
        Maybe you should have brought that up earlier instead of acting smug and burying the lede? It's also pretty telling that you didn't elaborate this further and kept your comment short. What you should have said is that some parameterized test generators do automated white box testing where they look at your code similar to a fuzzer and try to find the test cases automatically. Your first link is literally just setting up an array with test cases, which basically means you'd have to use an LLM to quickly produce the test cases anyway, which makes parameterized testing sound exceedingly pathetic. https://learn.microsoft.com/en-us/visualstudio/test/generate-unit-tests-for-your-code-with-intellitest?view=vs-2022 https://learn.microsoft.com/en-us/visualstudio/test/generate... >IntelliTest explores your .NET code to generate test data and a suite of unit tests. For every statement in the code, a test input is generated that will execute that statement. A case analysis is performed for every conditional branch in the code. For example, if statements, assertions, and all operations that can throw exceptions are analyzed. This analysis is used to generate test data for a parameterized unit test for each of your methods, creating unit tests with high code coverage. Think of it as smart fuzz testing that trims down the inputs and test cases to what executes all your logic branches and checks for exceptions.
  - imtringued 1y ago
    99% of the work in testing is coming up with test scenarios and test cases. 95% of the code is just dealing with setting up input and output data, 4% is calling the code you want to test and the final assert is often just a single line of code. I'm not sure what depth of experience has to do with any of this, since it is busy work that costs a lot of time. A form with 120 fields is a form with 120 fields. There is no way around coming up with the several dozens of test cases that you're going to test without filling out almost all of the fields, even the ones that are not relevant to the test itself, otherwise you're not really testing your application.
- goosejuice 1y ago
  We're not a licensed profession with universally defined roles. It's whatever the speaker wants it to be given how wildly it varies.