Install via Package Control.
afa - assert.fail
assert.fail(${1:actual}, ${2:expected}, ${3:message}, ${4:operator});
ass - assert
assert(${1:actual}${2:, ${3:message}});
aok - assert.ok
assert.ok(${1:actual}${2:, ${3:message}});
aeq - assert.equal
assert.equal(${1:actual}, ${2:expected}${3:, ${4:message}});
ane - assert.notEqual
assert.notEqual(${1:actual}, ${2:expected}${3:, ${4:message}});
ade - assert.deepEqual
assert.deepEqual(${1:actual}, ${2:expected}${3:, ${4:message}});
ande - assert.notDeepEqual
assert.notDeepEqual(${1:actual}, ${2:expected}${3:, ${4:message}});
ase - assert.strictEqual
assert.strictEqual(${1:actual}, ${2:expected}${3:, ${4:message}});
anse - assert.notStrictEqual
assert.notStrictEqual(${1:actual}, ${2:expected}${3:, ${4:message}});
adse - assert.deepStrictEqual
assert.deepStrictEqual(${1:actual}, ${2:expected}${3:, ${4:message}});
andse - assert.notDeepStrictEqual
assert.notDeepStrictEqual(${1:actual}, ${2:expected}${3:, ${4:message}});
ath - assert.throws
assert.throws(${1:block}${2:, ${3:error}}${4:, ${5:message}});
adnt - assert.doesNotThrow
assert.doesNotThrow(${1:block}${2:, ${3:error}}${4:, ${5:message}});
aif - assert.ifError
assert.ifError(${1:value});