assert – Page 11 – Tarik Billa

Why doesn’t JUnit provide assertNotEquals methods?

September 17, 2022 by Tarik

I’d suggest you use the newer assertThat() style asserts, which can easily describe all kinds of negations and automatically build a description of what you expected and what you got if the assertion fails: assertThat(objectUnderTest, is(not(someOtherObject))); assertThat(objectUnderTest, not(someOtherObject)); assertThat(objectUnderTest, not(equalTo(someOtherObject))); All three options are equivalent, choose the one you find most readable. To use the … Read more

Best practice for using assert?

September 12, 2022 by Tarik

Asserts should be used to test conditions that should never happen. The purpose is to crash early in the case of a corrupt program state. Exceptions should be used for errors that can conceivably happen, and you should almost always create your own Exception classes. For example, if you’re writing a function to read from … Read more

How to automatically generate a stacktrace when my program crashes

September 9, 2022 by Tarik

For Linux and I believe Mac OS X, if you’re using gcc, or any compiler that uses glibc, you can use the backtrace() functions in execinfo.h to print a stacktrace and exit gracefully when you get a segmentation fault. Documentation can be found in the libc manual. Here’s an example program that installs a SIGSEGV … Read more

How do I use Assert to verify that an exception has been thrown?

September 6, 2022 by Tarik

For “Visual Studio Team Test” it appears you apply the ExpectedException attribute to the test’s method. Sample from the documentation here: A Unit Testing Walkthrough with Visual Studio Team Test [TestMethod] [ExpectedException(typeof(ArgumentException), “A userId of null was inappropriately allowed.”)] public void NullUserIdInConstructor() { LogonInfo logonInfo = new LogonInfo(null, “P@ss0word”); }

What is the use of “assert” in Python?

August 29, 2022 by Tarik

The assert statement exists in almost every programming language. It has two main uses: It helps detect problems early in your program, where the cause is clear, rather than later when some other operation fails. A type error in Python, for example, can go through several layers of code before actually raising an Exception if … Read more

How do you assert that a certain exception is thrown in JUnit tests?

August 26, 2022 by Tarik

It depends on the JUnit version and what assert libraries you use. For JUnit5 and 4.13 see answer https://stackoverflow.com/a/2935935/2986984 If you use assertJ or google-truth, see answer https://stackoverflow.com/a/41019785/2986984 The original answer for JUnit <= 4.12 was: @Test(expected = IndexOutOfBoundsException.class) public void testIndexOutOfBoundsException() { ArrayList emptyList = new ArrayList(); Object o = emptyList.get(0); } Though answer … Read more