Watch the explanation. Practice the skill.
Command line, Git, Python, and environments
Make your program run from a clean copy, not just your own folder.
Captions appear here during playback.
Command line, Git, Python, and environments
Make your program run from a clean copy, not just your own folder.
Video playback is unavailable. Read the descriptive transcript below, go directly to practice, or open the video file.
Source-based teaching example · Fictional data · Reviewed 2026-10-03. Microsoft Mark · locally synthesized. On a small screen, use fullscreen for diagram details or read the transcript.
Read the descriptive transcript
0:00 · What you will learn
Make your program run from a clean copy, not just your own folder.
What appears on screen
Make your program run from a clean copy, not just your own folder.
0:07 · The idea
Record the setup and dependency versions. Test valid records and records that must fail. Ask whether another person can repeat the run using your instructions.
What appears on screen
Record the setup and dependency versions. Test valid records and records that must fail. Ask whether another person can repeat the run using your instructions.
0:20 · One useful term
Dependency. Other software your program needs to run.
What appears on screen
Other software your program needs to run.
0:27 · A worked example
The CSV exercise normalizes records and checks missing IDs and duplicates. A peer starts from an empty directory and runs the documented test command. That run provides evidence beyond “it worked on my machine.”
What appears on screen
The CSV exercise normalizes records and checks missing IDs and duplicates. A peer starts from an empty directory and runs the documented test command. That run provides evidence beyond “it worked on my machine.”
0:44 · Your turn to think
If the clean copy fails, should you immediately rewrite the program? Pause and decide before continuing.
What appears on screen
If the clean copy fails, should you immediately rewrite the program? Pause the video if you need more time.
1:02 · Why this answer works
First compare the Python version and working directory. Passing tests does not separately prove that dependencies come from trusted sources.
What appears on screen
First compare the Python version and working directory. Passing tests does not separately prove that dependencies come from trusted sources.
1:14 · Check 1
Record exact setup and test commands.
What appears on screen
Record exact setup and test commands.
1:19 · Check 2
Test valid and invalid records.
What appears on screen
Test valid and invalid records.
1:25 · Check 3
Check dependency origin as well as behavior.
What appears on screen
Check dependency origin as well as behavior.
1:30 · Now try a different case
Open the lesson and try its different practice case. Use every check in the full task. Watching alone does not mark the lesson complete.
What appears on screen
Open the lesson Try the new case Check and revise The full task and its requirements are in the linked lesson.
Watching explains the example. Complete the lesson practice to check what you can do. Explore all visual lessons →