From 12253499782abd6f269632cbf5d20ed62f685c7f Mon Sep 17 00:00:00 2001
From: jbranchaud <jbranchaud@gmail.com>
Date: Wed, 29 Jul 2026 01:00:46 -0500
Subject: [PATCH] Add Dedent Common Whitespace From Multiline String as a
 Python TIL

---
 README.md                                     |  3 +-
 ...common-whitespace-from-multiline-string.md | 46 +++++++++++++++++++
 2 files changed, 48 insertions(+), 1 deletion(-)
 create mode 100644 python/dedent-common-whitespace-from-multiline-string.md

diff --git a/README.md b/README.md
index 629c5b7..bd706c0 100644
--- a/README.md
+++ b/README.md
@@ -10,7 +10,7 @@ working across different projects via [VisualMode](https://www.visualmode.dev/).
 
 For a steady stream of TILs, [sign up for my newsletter](https://visualmode.kit.com/newsletter).
 
-_1843 TILs and counting..._
+_1844 TILs and counting..._
 
 See some of the other learning resources I work on:
 
@@ -1084,6 +1084,7 @@ If you've learned something here, support my efforts writing daily TILs by
 - [Control Passing Of Time In Tests](python/control-passing-of-time-in-tests.md)
 - [Create A Dummy DataFrame In Pandas](python/create-a-dummy-dataframe-in-pandas.md)
 - [Create A Range Of Descending Values](python/create-a-range-of-descending-values.md)
+- [Dedent Common Whitespace From Multiline String](python/dedent-common-whitespace-from-multiline-string.md)
 - [Deduplicate A List Into A Tuple](python/deduplicate-a-list-into-a-tuple.md)
 - [Define Sequence Of Tests With Parametrize Decorator](python/define-sequence-of-tests-with-parametrize-decorator.md)
 - [Define Typed Class Interface With Protocol](python/define-typed-class-interface-with-protocol.md)
diff --git a/python/dedent-common-whitespace-from-multiline-string.md b/python/dedent-common-whitespace-from-multiline-string.md
new file mode 100644
index 0000000..9ca9d07
--- /dev/null
+++ b/python/dedent-common-whitespace-from-multiline-string.md
@@ -0,0 +1,46 @@
+# Dedent Common Whitespace From Multiline String
+
+I'm adding tests to cover some custom logic in the _usage_ messages that are
+produced by Click [in a CLI I'm building](https://github.com/jbranchaud/py-vmt).
+The usage output is a mutliline string formatted with some indentation. On top
+of that, I'm putting it in a Python test file with some additional syntactical
+indentation.
+
+If this was Ruby, I would reach for the `<<~` heredoc syntax. The closest
+equivalent to that in Python is
+[`textwrap.dedent`](https://docs.python.org/3/library/textwrap.html#textwrap.dedent).
+
+> Remove any common leading whitespace from every line in text.
+> 
+> This can be used to make triple-quoted strings line up with the left edge of
+> the display, while still presenting them in the source code in indented form.
+
+```python
+import textwrap
+
+def test_base_help_message():
+    runner = BetterCliRunner()
+
+    help_result = runner.invoke(cli, ["--help"])
+    output = textwrap.dedent("""\
+    Usage: vmt [OPTIONS] COMMAND [ARGS]...
+
+    Options:
+      -v, --verbose  See extra output when running commands
+      --help         Show this message and exit.
+
+    Commands:
+      cancel
+      log
+      start
+      status
+      stop
+    """)
+    assert output in help_result.output
+```
+
+Before adding in `textwrap.dedent`, the test was failing because of bits of
+extra whitespace that wasn't matching up with the actual CLI output.
+
+Note: the leading `\` after the opening `"""` is needed to remove the leading
+newline that would otherwise be included.