Add a callout to remind learners to activate virtual env

episodes/21-automatically-testing-software.md

@@ -46,6 +46,19 @@ improve the predictability of a software change,
 make development more productive,
 and help us produce code that works as expected and produces desired results.
 
+::: callout
+
+### Activate your virtual environment
+If it is not already active, make sure to activate your virtual environment, called `venv`, 
+from the root of the software project directory:
+
+```bash
+$ source venv/bin/activate # Mac or Linux
+$ source venv/Scripts/activate # Windows
+(venv) $
+```
+:::
+
 ## What Is Software Testing?
 
 For the sake of argument, if each line we write has a 99% chance of being right,

episodes/31-software-requirements.md

@@ -20,12 +20,27 @@ exercises: 15
 
 ::::::::::::::::::::::::::::::::::::::::::::::::::
 
+## Introduction 
+
 The requirements of our software are the basis on which the whole project rests -
 if we get the requirements wrong, we will build the wrong software.
 However, it is unlikely that we will be able to determine all of the requirements upfront.
 Especially when working in a research context,
 requirements are flexible and may change as we develop our software.
 
+::: callout
+
+### Activate your virtual environment
+If it is not already active, make sure to activate your virtual environment, called `venv`,
+from the root of the software project directory:
+
+```bash
+$ source venv/bin/activate # Mac or Linux
+$ source venv/Scripts/activate # Windows
+(venv) $
+```
+:::
+
 ## Types of Requirements
 
 Requirements can be categorised in many ways,

episodes/41-code-review.md

@@ -29,6 +29,19 @@ Software is often designed and built as part of a team,
 so in this episode we will be looking at how to manage the process of team software development
 and improve our code by engaging in code review process with other team members.
 
+::: callout
+
+### Activate your virtual environment
+If it is not already active, make sure to activate your virtual environment, called `venv`,
+from the root of the software project directory:
+
+```bash
+$ source venv/bin/activate # Mac or Linux
+$ source venv/Scripts/activate # Windows
+(venv) $
+```
+:::
+
 ## Collaborative Code Development Models
 
 The way a team provides contributions to a shared codebase depends on

episodes/51-managing-software.md

@@ -34,6 +34,19 @@ it can be hard to keep track of what's done, or what needs doing,
 and particularly difficult to convey that to others
 in the team or share the responsibilities.
 
+::: callout
+
+### Activate your virtual environment
+If it is not already active, make sure to activate your virtual environment, called `venv`,
+from the root of the software project directory:
+
+```bash
+$ source venv/bin/activate # Mac or Linux
+$ source venv/Scripts/activate # Windows
+(venv) $
+```
+:::
+
 ## Using GitHub to Manage Issues With Software
 
 As a piece of software is used,