Nodejs学习笔记——Assert(断言)

时间:2022-12-07 21:35:34
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)
assert.fail(a, e, m, o)

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,"","+")

assert(v, [m]), assert.ok(v, [m])

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")

assert.equal(a, e, [m])

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")

assert.notEqual(a, e, [m])

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。

assert.deepEqual(a, e, [m])

Tests for deep equality.

Note: 不清楚!

assert.notDeepEqual(a, e, [m])

Tests for any deep inequality.

Note: 不清楚!

assert.strictEqual(a, e, [m])

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

assert.notStrictEqual(a, e, [m])

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

assert.throws(b, [error], [m])

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"
);
assert.doesNotThrow(b, [m])

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

assert.ifError(v)

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!