test: improve test stream transform constructor
- new test for the error when a transform function is not specified
- use let instead of var
- use assert.strictEqual instead of assert.equal
- use arrow functions
Checklist
-
make -j4 test
(UNIX), orvcbuild test
(Windows) passes -
tests and/or benchmarks are included -
commit message follows commit guidelines
Affected core subsystem(s)
test