WIP: attempt to write a blurb of git-style test

The tests won't work outside of the git tree. Perhaps, I should
just rewrite it to plain shell script. Should I?

Author: mcepl

.github/workflows/shellcheck.yml

@@ -15,4 +15,4 @@ jobs:
       - name: Run ShellCheck
         uses: ludeeus/action-shellcheck@master
         with:
-            ignore_paths: ./completion.*
+            ignore_paths: ./completion.* ./t/*

t/t7600-fixup.sh

@@ -0,0 +1,26 @@
+#!/bin/sh
+
+test_description='.'
+
+export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
+
+TEST_PASSES_SANITIZE_LEAK=true
+. ./test-lib.sh
+
+test_expect_success 'setup' '
+    git init almost-complete
+    cd almost-complete/
+    
+    echo "Testing file 1" >test_01.txt
+    git add test_01.txt
+    git commit -m "Commiting the first file."
+    echo "Testing file 2" >test_02.txt
+    git add test_02.txt 
+    git commit -m "Commiting the second file."
+    echo "Modifying the first file." >>test_01.txt 
+    git add test_01.txt 
+    # git fixup --no-commit |grep -s "something"
+    /bin/true
+'
+
+test_done