string-contains

C# – Ignore case with string.Contains()

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By default, string.Contains() does a case sensitive search for a substring (or character) in a string. You can make it do a case insensitive search instead by passing in StringComparison.OrdinalIgnoreCase, like this: Note: StringComparison has three ‘ignore case’ options to choose from. Because this is doing a case insensitive search, it matched “earth” to “Earth” … Read more

C# – Find a character in a string

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There are three methods you can use to find a character in a string: I’ll show examples below. Using string.IndexOf() to find a character string.IndexOf() returns the index of the first occurrence of a character in a string. It searches the string from left to right, starting at the beginning. If it doesn’t find the … Read more

Moq – Verifying parameters passed to a mocked method

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When you need to verify that the code under test called a method with the expected parameters, you can mock the method with Moq and use Verify() + It.Is<T>() to check the parameters passed in. Verify() asserts that the method call happened as expected with the specified parameters. Here’s an example. This is verifying that … Read more

C# – Check if a string contains any substring from a list

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There are many different scenarios where you might want to check a string against a list of substrings. Perhaps you’re dealing with messy exception handling and have to compare the exception message against a list of known error messages to determine if the error is transient or not. When you need to check a string … Read more

C# – Use StringAssert when testing a string for substrings

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When you’re testing if two strings are equal, you can simply use Assert.AreEqual(). When you’re testing if a string contains a substring or a pattern, typically developers use Assert.IsTrue() with a substring method or regex. You should use StringAssert instead, because it gives better failure messages. Note: StringAssert is nice because it’s a built-in class. … Read more