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+# Error assertions
+
+Error related assertions, to verify error generation and error messages.
+
+* **_AFT.assertError(func, ...)**
+
+    Assert that calls to the function **func** with the arguments yields an error. If the function does
+    not yield an error, the assertion fails.
+
+    Note that the error message itself is not checked, which means that this function does not
+    distinguish between the legitimate error that you expect and another error that might be
+    triggered by mistake.
+
+    The next functions provide a better approach to error testing, by checking explicitly the error
+    message content.
+
+>**Note**
+>When testing LuaUnit, switching from assertError() to assertErrorMsgEquals() revealed quite a few bugs!
+
+* **_AFT.assertErrorMsgEquals(expectedMsg, func, ...)**
+
+    Assert that calls to the function **func** will generate exactly the given error message. If the
+    function does not yield an error, or if the error message is not identical, the assertion fails.
+
+    Be careful when using this function that error messages usually contain the file name and line
+    number information of where the error was generated. This is usually inconvenient. To ignore the
+    filename and line number information, you can either use a pattern with assertErrorMsgMatches()
+    or simply check if the message contains a string with assertErrorMsgContains() .
+
+* **_AFT.assertErrorMsgContains(partialMsg, func, ...)**
+
+    Assert that calls to the function **func** will generate an error message containing partialMsg.
+    If the function does not yield an error, or if the expected message is not contained in the
+    error message, the assertion fails.
+
+* **_AFT.assertErrorMsgMatches(expectedPattern, func, ...)**
+
+    Assert that calls to the function **func** will generate an error message matching expectedPattern.
+    If the function does not yield an error, or if the error message does not match the provided
+    pattern the assertion fails.
+
+    Note that matching is done from the start to the end of the error message. Be sure to escape
+    magic all magic characters with % (like -+.?\*) .
+\ No newline at end of file