In computer programming, unit testing is a software testing method by which individual units of source code are tested to determine whether they are fit for use. [1] - from wikipedia
Integration testing is the phase in software testing in which individual software modules are combined and tested as a group. - from wikipedia
1 - Kolawa, Adam; Huizinga, Dorota (2007). Automated Defect Prevention: Best Practices in Software Management. Wiley-IEEE Computer Society Press. p. 75. ISBN 978-0-470-04212-0. https://en.wikipedia.org/wiki/Unit_testing