Nodejs学习笔记——Assert（断言）
- Assert - a:actual e:expected m:message o:operator v:value b:block
- assert.fail(a, e, m, o)
- assert(v, m), assert.ok(v, [m])
- assert.equal(a, e, [m])
- assert.notEqual(a, e, [m])
- assert.deepEqual(a, e, [m])
- assert.notDeepEqual(a, e, [m])
- assert.strictEqual(a, e, [m])
- assert.notStrictEqual(a, e, [m])
- assert.throws(b, [error], [m])
- assert.doesNotThrow(b, [m])
- assert.ifError(v)
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: 采用以下步骤比较，只要一个步骤不匹配就抛出异常：
- 采用
===比较； - 比较他们是否是Buffers，如果是则比较长度，接下来每字节每字节比较；
- 用
==比较； - 最后如果参数是Object对象，则比较他们的属性长度和属性值
Tests for any deep inequality.
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!
