+#
+# Case #0
+#
+############################################################
+#
+# Input:
+#
+# - GIT_WORK_TREE is not set
+# - GIT_DIR is not set
+# - core.worktree is not set
+# - .git is a directory
+# - core.bare is not set, cwd is outside .git
+#
+# Output:
+#
+# - worktree is .git's parent directory
+# - cwd is at worktree root dir
+# - prefix is calculated
+# - git_dir is set to ".git"
+# - cwd can't be outside worktree
+
+test_expect_success '#0: setup' '
+ unset GIT_DIR GIT_WORK_TREE &&
+ mkdir 0 0/sub &&
+ cd 0 && git init && cd ..
+'
+
+test_expect_success '#0: at root' '
+ cat >0/expected <<EOF &&
+setup: git_dir: .git
+setup: worktree: $TRASH_DIRECTORY/0
+setup: cwd: $TRASH_DIRECTORY/0
+setup: prefix: (null)
+EOF
+ test_repo 0
+'
+
+test_expect_success '#0: in subdir' '
+ cat >0/sub/expected <<EOF &&
+setup: git_dir: .git
+setup: worktree: $TRASH_DIRECTORY/0
+setup: cwd: $TRASH_DIRECTORY/0
+setup: prefix: sub/
+EOF
+ test_repo 0/sub
+'
+