Regular Expressions: Look ahead and Look behind

Regular expressions are fun. There are two important concepts that are quite often sought for. Find something based on content that follows our search pattern . OR. Find something based on content that lies ahead. Let's see some examples to see what I mean.

LOOK AHEAD

LOOK AHEAD means , I want to see what lies ahead first, and then decide, to do something now.

Syntax of regex pattern:  pattern1(?=pattern2)

Calling Flask URL from a script tag

The goal is , to call a FLASK route without reloading the page, when a button is pressed. The content of a div must change with the response text received from the flask route call.

How to use Python unit test module and it's methods?

Unit test module is an in-build library in python, used to write test scripts . It gives some helpful methods while helps us designing out test in a way , that emulates a real production environment.

While writing test, we need to keep these things in mind

1. Test should start with a clean slate. Meaning the subject under test must not hold any info or be in a state, that might affect the test results.

2. Every tests should test one and only one feature . Clubbing multiple tests in one test,  is a bad idea.

Unit test provides some special methods. These can be used to handle the flow of tests as per scenario. Below is a generic template of a unit test showing all methods and their tasks.