Nodejs学习笔记——Assert（断言）

Throws an exception that displays the values for actual and expected separated by the provided operator.

Note: Always throws an exception and display the message which will be "actual operator expected" if it‘s omited.

e.g assert.fail(1,1,"Always throws this message","=") and assert.fail(1,1,"","+")

Tests if value is truthy, it is equivalent to assert.equal(true, !!value, message);

Note: If the value isn‘t a truth-value, it throws and exception and display the message which will be "value == true" if it‘s omited.

e.g assert(0) and assert.ok(0,"Throws me")

Tests shallow, coercive equality with the equal comparison operator ( == ).

e.g assert.equal(1,2,"They are not equal") and assert.equal(1,1,"would not show me")

Tests shallow, coercive non-equality with the not equal comparison operator ( != ).

Note: 综上，是对比结果为false时抛出异常。

Tests for deep equality.

Note: 不清楚！

Tests for any deep inequality.

Note: 不清楚！

Tests strict equality, as determined by the strict equality operator ( === )

Tests strict non-equality, as determined by the strict not equal operator ( !== )

Expects block to throw an error. error can be constructor, RegExp or validation function.

Validate instanceof using constructor:

assert.throws(
	function() {
		throw new Error("Wrong value");
	},
	Error
);
		

Validate error message using RegExp:

assert.throws(
	function() {
		throw new Error("Wrong value");
	},
	/value/
);
		

Custom error validation:

assert.throws(
	function() {
		throw new Error("Wrong value");
	},
	function(err) {
		if ( (err instanceof Error) && /value/.test(err) ) {
			return true;
		}
	},
	"unexpected error"
);
		

Expects block not to throw an error, see assert.throws for details.

Tests if value is not a false value, throws if it is a true value. Useful when testing the first argument, error in callbacks.

Note: it throws error when the value is a truth-value!