diff --git a/t/t9904-completion-zsh.sh b/t/t9904-completion-zsh.sh
new file mode 100755
index 0000000000..65bdaa011e
--- /dev/null
+++ b/t/t9904-completion-zsh.sh
@@ -0,0 +1,1143 @@
+#!/bin/sh
+#
+# Copyright (c) 2012-2023 Felipe Contreras
+#
+
+test_description='test zsh completion'
+
+if test -n "$ZSH_VERSION"; then
+	true
+elif command -v zsh > /dev/null 2>&1; then
+	exec zsh "$0" "$@"
+else
+	echo '1..0 #SKIP skipping zsh completion tests: zsh not available'
+	exit 0
+fi
+
+export ZDOTDIR="${0:h:a}/t9904"
+
+. ./test-lib.sh
+
+emulate zsh
+
+zmodload zsh/zpty
+
+export SRC_DIR="$GIT_BUILD_DIR/contrib/completion/"
+
+run_completion ()
+{
+	local log
+
+	# bug in zsh: reset the exit trap
+	zpty zsh "trap - EXIT; zsh -o NO_GLOBAL_RCS"
+	zpty -n -w zsh "$1"$'\t'
+	zpty -r zsh log '*<END-CHOICES>'
+	zpty -d zsh
+
+	printf '%s\n' ${${${(M)${(Qf)log}:#*'<MARK>'*}#*'<MARK>'}%'</MARK>'*} > out
+
+	[[ -s out ]] || { echo > out ; }
+}
+
+# Test high-level completion
+# Arguments are:
+# 1: typed text so far (cur)
+# 2: expected completion
+test_completion ()
+{
+	if test $# -gt 1
+	then
+		printf '%s\n' "$2" >expected
+	else
+		sed -e 's/Z$//' |sort >expected
+	fi &&
+	run_completion "$1" &&
+	sort -u out >out_sorted &&
+	test_cmp expected out_sorted
+}
+
+# Test __gitcomp.
+# The first argument is the typed text so far (cur); the rest are
+# passed to __gitcomp.  Expected output comes is read from the
+# standard input, like test_completion().
+test_gitcomp ()
+{
+	sed -e 's/Z$//' >expected &&
+	local cur="$1" &&
+	shift &&
+	run_completion "git func __gitcomp $(printf "%q " "$@") $cur" &&
+	test_cmp expected out
+}
+
+# Test __gitcomp_nl
+# Arguments are:
+# 1: current word (cur)
+# -: the rest are passed to __gitcomp_nl
+test_gitcomp_nl ()
+{
+	sed -e 's/Z$//' >expected &&
+	local cur="$1" &&
+	shift &&
+	run_completion "git func __gitcomp_nl $(printf "%q " "$@") $cur" &&
+	test_cmp expected out
+}
+
+actual="$TRASH_DIRECTORY/actual"
+
+if test_have_prereq MINGW
+then
+	ROOT="$(pwd -W)"
+else
+	ROOT="$(pwd)"
+fi
+
+test_expect_success 'setup for __git_find_repo_path/__gitdir tests' '
+	mkdir -p subdir/subsubdir &&
+	mkdir -p non-repo &&
+	git init -b main otherrepo
+'
+
+test_expect_success '__gitcomp - trailing space - options' '
+	test_gitcomp "--re" "--dry-run --reuse-message= --reedit-message=
+		--reset-author" <<-EOF
+	--reuse-message=Z
+	--reedit-message=Z
+	--reset-author Z
+	EOF
+'
+
+test_expect_success '__gitcomp - trailing space - config keys' '
+	test_gitcomp "br" "branch. branch.autosetupmerge
+		branch.autosetuprebase browser." <<-\EOF
+	branch.Z
+	branch.autosetupmerge Z
+	branch.autosetuprebase Z
+	browser.Z
+	EOF
+'
+
+test_expect_success '__gitcomp - option parameter' '
+	test_gitcomp "--strategy=re" "octopus ours recursive resolve subtree" \
+		"" "re" <<-\EOF
+	recursive Z
+	resolve Z
+	EOF
+'
+
+test_expect_failure '__gitcomp - prefix' '
+	test_gitcomp "branch.me" "remote merge mergeoptions rebase" \
+		"branch.maint." "me" <<-\EOF
+	branch.maint.merge Z
+	branch.maint.mergeoptions Z
+	EOF
+'
+
+test_expect_failure '__gitcomp - suffix' '
+	test_gitcomp "branch.me" "master maint next seen" "branch." \
+		"ma" "." <<-\EOF
+	branch.master.Z
+	branch.maint.Z
+	EOF
+'
+
+test_expect_success '__gitcomp - ignore optional negative options' '
+	test_gitcomp "--" "--abc --def --no-one -- --no-two" <<-\EOF
+	--abc Z
+	--def Z
+	--no-one Z
+	--no-... Z
+	EOF
+'
+
+test_expect_success '__gitcomp - ignore/narrow optional negative options' '
+	test_gitcomp "--a" "--abc --abcdef --no-one -- --no-two" <<-\EOF
+	--abc Z
+	--abcdef Z
+	EOF
+'
+
+test_expect_success '__gitcomp - ignore/narrow optional negative options' '
+	test_gitcomp "--n" "--abc --def --no-one -- --no-two" <<-\EOF
+	--no-one Z
+	--no-... Z
+	EOF
+'
+
+test_expect_success '__gitcomp - expand all negative options' '
+	test_gitcomp "--no-" "--abc --def --no-one -- --no-two" <<-\EOF
+	--no-one Z
+	--no-two Z
+	EOF
+'
+
+test_expect_success '__gitcomp - expand/narrow all negative options' '
+	test_gitcomp "--no-o" "--abc --def --no-one -- --no-two" <<-\EOF
+	--no-one Z
+	EOF
+'
+
+test_expect_failure '__gitcomp - equal skip' '
+	test_gitcomp "--option=" "--option=" <<-\EOF &&
+
+	EOF
+	test_gitcomp "option=" "option=" <<-\EOF
+
+	EOF
+'
+
+read -r -d "" refs <<-\EOF
+main
+maint
+next
+seen
+EOF
+
+test_expect_success '__gitcomp_nl - trailing space' '
+	test_gitcomp_nl "m" "$refs" <<-EOF
+	main Z
+	maint Z
+	EOF
+'
+
+test_expect_failure '__gitcomp_nl - prefix' '
+	test_gitcomp_nl "--fixup=m" "$refs" "--fixup=" "m" <<-EOF
+	--fixup=main Z
+	--fixup=maint Z
+	EOF
+'
+
+test_expect_success '__gitcomp_nl - suffix' '
+	test_gitcomp_nl "branch.ma" "$refs" "branch." "ma" "." <<-\EOF
+	branch.main.Z
+	branch.maint.Z
+	EOF
+'
+
+test_expect_success '__gitcomp_nl - no suffix' '
+	test_gitcomp_nl "ma" "$refs" "" "ma" "" <<-\EOF
+	mainZ
+	maintZ
+	EOF
+'
+
+test_expect_success 'setup for ref completion' '
+	git commit --allow-empty -m initial &&
+	git branch -M main &&
+	git branch matching-branch &&
+	git tag matching-tag &&
+	(
+		cd otherrepo &&
+		git commit --allow-empty -m initial &&
+		git branch -m main main-in-other &&
+		git branch branch-in-other &&
+		git tag tag-in-other
+	) &&
+	git remote add other "$ROOT/otherrepo/.git" &&
+	git fetch --no-tags other &&
+	rm -f .git/FETCH_HEAD &&
+	git init thirdrepo
+'
+
+test_expect_success 'git switch - with no options, complete local branches and unique remote branch names for DWIM logic' '
+	test_completion "git switch " <<-\EOF
+	branch-in-other Z
+	main Z
+	main-in-other Z
+	matching-branch Z
+	EOF
+'
+
+test_expect_success 'git checkout - completes refs and unique remote branches for DWIM' '
+	test_completion "git checkout " <<-\EOF
+	HEAD Z
+	branch-in-other Z
+	main Z
+	main-in-other Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/main-in-other Z
+	EOF
+'
+
+test_expect_success 'git switch - with --no-guess, complete only local branches' '
+	test_completion "git switch --no-guess " <<-\EOF
+	main Z
+	matching-branch Z
+	EOF
+'
+
+test_expect_success 'git switch - with GIT_COMPLETION_CHECKOUT_NO_GUESS=1, complete only local branches' '
+	GIT_COMPLETION_CHECKOUT_NO_GUESS=1 test_completion "git switch " <<-\EOF
+	main Z
+	matching-branch Z
+	EOF
+'
+
+test_expect_success 'git switch - --guess overrides GIT_COMPLETION_CHECKOUT_NO_GUESS=1, complete local branches and unique remote names for DWIM logic' '
+	GIT_COMPLETION_CHECKOUT_NO_GUESS=1 test_completion "git switch --guess " <<-\EOF
+	branch-in-other Z
+	main Z
+	main-in-other Z
+	matching-branch Z
+	EOF
+'
+
+test_expect_success 'git switch - a later --guess overrides previous --no-guess, complete local and remote unique branches for DWIM' '
+	test_completion "git switch --no-guess --guess " <<-\EOF
+	branch-in-other Z
+	main Z
+	main-in-other Z
+	matching-branch Z
+	EOF
+'
+
+test_expect_success 'git switch - a later --no-guess overrides previous --guess, complete only local branches' '
+	test_completion "git switch --guess --no-guess " <<-\EOF
+	main Z
+	matching-branch Z
+	EOF
+'
+
+test_expect_success 'git checkout - with GIT_COMPLETION_NO_GUESS=1 only completes refs' '
+	GIT_COMPLETION_CHECKOUT_NO_GUESS=1 test_completion "git checkout " <<-\EOF
+	HEAD Z
+	main Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/main-in-other Z
+	EOF
+'
+
+test_expect_success 'git checkout - --guess overrides GIT_COMPLETION_NO_GUESS=1, complete refs and unique remote branches for DWIM' '
+	GIT_COMPLETION_CHECKOUT_NO_GUESS=1 test_completion "git checkout --guess " <<-\EOF
+	HEAD Z
+	branch-in-other Z
+	main Z
+	main-in-other Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/main-in-other Z
+	EOF
+'
+
+test_expect_success 'git checkout - with --no-guess, only completes refs' '
+	test_completion "git checkout --no-guess " <<-\EOF
+	HEAD Z
+	main Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/main-in-other Z
+	EOF
+'
+
+test_expect_success 'git checkout - a later --guess overrides previous --no-guess, complete refs and unique remote branches for DWIM' '
+	test_completion "git checkout --no-guess --guess " <<-\EOF
+	HEAD Z
+	branch-in-other Z
+	main Z
+	main-in-other Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/main-in-other Z
+	EOF
+'
+
+test_expect_success 'git checkout - a later --no-guess overrides previous --guess, complete only refs' '
+	test_completion "git checkout --guess --no-guess " <<-\EOF
+	HEAD Z
+	main Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/main-in-other Z
+	EOF
+'
+
+test_expect_success 'git checkout - with checkout.guess = false, only completes refs' '
+	test_config checkout.guess false &&
+	test_completion "git checkout " <<-\EOF
+	HEAD Z
+	main Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/main-in-other Z
+	EOF
+'
+
+test_expect_success 'git checkout - with checkout.guess = true, completes refs and unique remote branches for DWIM' '
+	test_config checkout.guess true &&
+	test_completion "git checkout " <<-\EOF
+	HEAD Z
+	branch-in-other Z
+	main Z
+	main-in-other Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/main-in-other Z
+	EOF
+'
+
+test_expect_success 'git checkout - a later --guess overrides previous checkout.guess = false, complete refs and unique remote branches for DWIM' '
+	test_config checkout.guess false &&
+	test_completion "git checkout --guess " <<-\EOF
+	HEAD Z
+	branch-in-other Z
+	main Z
+	main-in-other Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/main-in-other Z
+	EOF
+'
+
+test_expect_success 'git checkout - a later --no-guess overrides previous checkout.guess = true, complete only refs' '
+	test_config checkout.guess true &&
+	test_completion "git checkout --no-guess " <<-\EOF
+	HEAD Z
+	main Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/main-in-other Z
+	EOF
+'
+
+test_expect_success 'git switch - with --detach, complete all references' '
+	test_completion "git switch --detach " <<-\EOF
+	HEAD Z
+	main Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/main-in-other Z
+	EOF
+'
+
+test_expect_success 'git checkout - with --detach, complete only references' '
+	test_completion "git checkout --detach " <<-\EOF
+	HEAD Z
+	main Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/main-in-other Z
+	EOF
+'
+
+test_expect_success 'git switch - with -d, complete all references' '
+	test_completion "git switch -d " <<-\EOF
+	HEAD Z
+	main Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/main-in-other Z
+	EOF
+'
+
+test_expect_success 'git checkout - with -d, complete only references' '
+	test_completion "git checkout -d " <<-\EOF
+	HEAD Z
+	main Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/main-in-other Z
+	EOF
+'
+
+test_expect_success 'git switch - with --track, complete only remote branches' '
+	test_completion "git switch --track " <<-\EOF
+	other/branch-in-other Z
+	other/main-in-other Z
+	EOF
+'
+
+test_expect_success 'git checkout - with --track, complete only remote branches' '
+	test_completion "git checkout --track " <<-\EOF
+	other/branch-in-other Z
+	other/main-in-other Z
+	EOF
+'
+
+test_expect_success 'git switch - with --no-track, complete only local branch names' '
+	test_completion "git switch --no-track " <<-\EOF
+	main Z
+	matching-branch Z
+	EOF
+'
+
+test_expect_success 'git checkout - with --no-track, complete only local references' '
+	test_completion "git checkout --no-track " <<-\EOF
+	HEAD Z
+	main Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/main-in-other Z
+	EOF
+'
+
+test_expect_success 'git switch - with -c, complete all references' '
+	test_completion "git switch -c new-branch " <<-\EOF
+	HEAD Z
+	main Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/main-in-other Z
+	EOF
+'
+
+test_expect_success 'git switch - with -C, complete all references' '
+	test_completion "git switch -C new-branch " <<-\EOF
+	HEAD Z
+	main Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/main-in-other Z
+	EOF
+'
+
+test_expect_success 'git switch - with -c and --track, complete all references' '
+	test_completion "git switch -c new-branch --track " <<-EOF
+	HEAD Z
+	main Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/main-in-other Z
+	EOF
+'
+
+test_expect_success 'git switch - with -C and --track, complete all references' '
+	test_completion "git switch -C new-branch --track " <<-EOF
+	HEAD Z
+	main Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/main-in-other Z
+	EOF
+'
+
+test_expect_success 'git switch - with -c and --no-track, complete all references' '
+	test_completion "git switch -c new-branch --no-track " <<-\EOF
+	HEAD Z
+	main Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/main-in-other Z
+	EOF
+'
+
+test_expect_success 'git switch - with -C and --no-track, complete all references' '
+	test_completion "git switch -C new-branch --no-track " <<-\EOF
+	HEAD Z
+	main Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/main-in-other Z
+	EOF
+'
+
+test_expect_success 'git checkout - with -b, complete all references' '
+	test_completion "git checkout -b new-branch " <<-\EOF
+	HEAD Z
+	main Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/main-in-other Z
+	EOF
+'
+
+test_expect_success 'git checkout - with -B, complete all references' '
+	test_completion "git checkout -B new-branch " <<-\EOF
+	HEAD Z
+	main Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/main-in-other Z
+	EOF
+'
+
+test_expect_success 'git checkout - with -b and --track, complete all references' '
+	test_completion "git checkout -b new-branch --track " <<-EOF
+	HEAD Z
+	main Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/main-in-other Z
+	EOF
+'
+
+test_expect_success 'git checkout - with -B and --track, complete all references' '
+	test_completion "git checkout -B new-branch --track " <<-EOF
+	HEAD Z
+	main Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/main-in-other Z
+	EOF
+'
+
+test_expect_success 'git checkout - with -b and --no-track, complete all references' '
+	test_completion "git checkout -b new-branch --no-track " <<-\EOF
+	HEAD Z
+	main Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/main-in-other Z
+	EOF
+'
+
+test_expect_success 'git checkout - with -B and --no-track, complete all references' '
+	test_completion "git checkout -B new-branch --no-track " <<-\EOF
+	HEAD Z
+	main Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/main-in-other Z
+	EOF
+'
+
+test_expect_success 'git switch - for -c, complete local branches and unique remote branches' '
+	test_completion "git switch -c " <<-\EOF
+	branch-in-other Z
+	main Z
+	main-in-other Z
+	matching-branch Z
+	EOF
+'
+
+test_expect_success 'git switch - for -C, complete local branches and unique remote branches' '
+	test_completion "git switch -C " <<-\EOF
+	branch-in-other Z
+	main Z
+	main-in-other Z
+	matching-branch Z
+	EOF
+'
+
+test_expect_success 'git switch - for -c with --no-guess, complete local branches only' '
+	test_completion "git switch --no-guess -c " <<-\EOF
+	main Z
+	matching-branch Z
+	EOF
+'
+
+test_expect_success 'git switch - for -C with --no-guess, complete local branches only' '
+	test_completion "git switch --no-guess -C " <<-\EOF
+	main Z
+	matching-branch Z
+	EOF
+'
+
+test_expect_success 'git switch - for -c with --no-track, complete local branches only' '
+	test_completion "git switch --no-track -c " <<-\EOF
+	main Z
+	matching-branch Z
+	EOF
+'
+
+test_expect_success 'git switch - for -C with --no-track, complete local branches only' '
+	test_completion "git switch --no-track -C " <<-\EOF
+	main Z
+	matching-branch Z
+	EOF
+'
+
+test_expect_success 'git checkout - for -b, complete local branches and unique remote branches' '
+	test_completion "git checkout -b " <<-\EOF
+	branch-in-other Z
+	main Z
+	main-in-other Z
+	matching-branch Z
+	EOF
+'
+
+test_expect_success 'git checkout - for -B, complete local branches and unique remote branches' '
+	test_completion "git checkout -B " <<-\EOF
+	branch-in-other Z
+	main Z
+	main-in-other Z
+	matching-branch Z
+	EOF
+'
+
+test_expect_success 'git checkout - for -b with --no-guess, complete local branches only' '
+	test_completion "git checkout --no-guess -b " <<-\EOF
+	main Z
+	matching-branch Z
+	EOF
+'
+
+test_expect_success 'git checkout - for -B with --no-guess, complete local branches only' '
+	test_completion "git checkout --no-guess -B " <<-\EOF
+	main Z
+	matching-branch Z
+	EOF
+'
+
+test_expect_success 'git checkout - for -b with --no-track, complete local branches only' '
+	test_completion "git checkout --no-track -b " <<-\EOF
+	main Z
+	matching-branch Z
+	EOF
+'
+
+test_expect_success 'git checkout - for -B with --no-track, complete local branches only' '
+	test_completion "git checkout --no-track -B " <<-\EOF
+	main Z
+	matching-branch Z
+	EOF
+'
+
+test_expect_success 'git switch - with --orphan completes local branch names and unique remote branch names' '
+	test_completion "git switch --orphan " <<-\EOF
+	branch-in-other Z
+	main Z
+	main-in-other Z
+	matching-branch Z
+	EOF
+'
+
+test_expect_success 'git switch - --orphan with branch already provided completes nothing else' '
+	test_completion "git switch --orphan main " <<-\EOF
+
+	EOF
+'
+
+test_expect_success 'git checkout - with --orphan completes local branch names and unique remote branch names' '
+	test_completion "git checkout --orphan " <<-\EOF
+	branch-in-other Z
+	main Z
+	main-in-other Z
+	matching-branch Z
+	EOF
+'
+
+test_expect_success 'git checkout - --orphan with branch already provided completes local refs for a start-point' '
+	test_completion "git checkout --orphan main " <<-\EOF
+	HEAD Z
+	main Z
+	matching-branch Z
+	matching-tag Z
+	other/branch-in-other Z
+	other/main-in-other Z
+	EOF
+'
+
+test_expect_success 'teardown after ref completion' '
+	git branch -d matching-branch &&
+	git tag -d matching-tag &&
+	git remote remove other
+'
+
+test_expect_success 'basic' '
+	run_completion "git " &&
+	# built-in
+	grep -q "^add\$" out &&
+	# script
+	grep -q "^rebase\$" out &&
+	# plumbing
+	! grep -q "^ls-files\$" out &&
+
+	run_completion "git r" &&
+	! grep -q -v "^r" out
+'
+
+test_expect_success 'double dash "git" itself' '
+	test_completion "git --" <<-\EOF
+	--paginate
+	--no-pager
+	--git-dir
+	--bare
+	--version
+	--exec-path
+	--html-path
+	--man-path
+	--info-path
+	--work-tree
+	--namespace
+	--no-replace-objects
+	--help
+	EOF
+'
+
+test_expect_success 'double dash "git checkout"' '
+	test_completion "git checkout --" <<-\EOF
+	--quiet Z
+	--detach Z
+	--track Z
+	--orphan=Z
+	--ours Z
+	--theirs Z
+	--merge Z
+	--conflict=Z
+	--patch Z
+	--ignore-skip-worktree-bits Z
+	--ignore-other-worktrees Z
+	--recurse-submodules Z
+	--progress Z
+	--guess Z
+	--no-guess Z
+	--no-... Z
+	--overlay Z
+	--pathspec-file-nul Z
+	--pathspec-from-file=Z
+	EOF
+'
+
+test_expect_success 'general options' '
+	test_completion "git --ver" "--version" &&
+	test_completion "git --hel" "--help" &&
+	test_completion "git --exe" "--exec-path" &&
+	test_completion "git --htm" "--html-path" &&
+	test_completion "git --pag" "--paginate" &&
+	test_completion "git --no-p" "--no-pager" &&
+	test_completion "git --git" "--git-dir" &&
+	test_completion "git --wor" "--work-tree" &&
+	test_completion "git --nam" "--namespace" &&
+	test_completion "git --bar" "--bare" &&
+	test_completion "git --inf" "--info-path" &&
+	test_completion "git --no-r" "--no-replace-objects"
+'
+
+test_expect_failure 'general options plus command' '
+	test_completion "git --version check" "" &&
+	test_completion "git --paginate check" "checkout" &&
+	test_completion "git --git-dir=foo check" "checkout" &&
+	test_completion "git --bare check" "checkout" &&
+	test_completion "git --exec-path=foo check" "checkout" &&
+	test_completion "git --html-path check" "" &&
+	test_completion "git --no-pager check" "checkout" &&
+	test_completion "git --work-tree=foo check" "checkout" &&
+	test_completion "git --namespace=foo check" "checkout" &&
+	test_completion "git --paginate check" "checkout" &&
+	test_completion "git --info-path check" "" &&
+	test_completion "git --no-replace-objects check" "checkout" &&
+	test_completion "git --git-dir some/path check" "checkout" &&
+	test_completion "git -c conf.var=value check" "checkout" &&
+	test_completion "git -C some/path check" "checkout" &&
+	test_completion "git --work-tree some/path check" "checkout" &&
+	test_completion "git --namespace name/space check" "checkout"
+'
+
+test_expect_success 'git --help completion' '
+	test_completion "git --help ad" "add " &&
+	test_completion "git --help core" "core-tutorial "
+'
+
+test_expect_success 'setup for integration tests' '
+	echo content >file1 &&
+	echo more >file2 &&
+	git add file1 file2 &&
+	git commit -m one &&
+	git branch mybranch &&
+	git tag mytag
+'
+
+test_expect_success 'checkout completes ref names' '
+	test_completion "git checkout m" <<-\EOF
+	main Z
+	mybranch Z
+	mytag Z
+	EOF
+'
+
+test_expect_failure 'git -C <path> checkout uses the right repo' '
+	test_completion "git -C subdir -C subsubdir -C .. -C ../otherrepo checkout b" <<-\EOF
+	branch-in-other Z
+	EOF
+'
+
+test_expect_success 'show completes all refs' '
+	test_completion "git show m" <<-\EOF
+	main Z
+	mybranch Z
+	mytag Z
+	EOF
+'
+
+test_expect_success '<ref>: completes paths' '
+	test_completion "git show mytag:f" <<-\EOF
+	file1Z
+	file2Z
+	EOF
+'
+
+test_expect_success 'complete tree filename with spaces' '
+	echo content >"name with spaces" &&
+	git add "name with spaces" &&
+	git commit -m spaces &&
+	test_completion "git show HEAD:nam" <<-\EOF
+	name with spacesZ
+	EOF
+'
+
+test_expect_success 'complete tree filename with metacharacters' '
+	echo content >"name with \${meta}" &&
+	git add "name with \${meta}" &&
+	git commit -m meta &&
+	test_completion "git show HEAD:nam" <<-\EOF
+	name with ${meta}Z
+	name with spacesZ
+	EOF
+'
+
+test_expect_success PERL 'send-email' '
+	test_completion "git send-email --cov" <<-\EOF &&
+	--cover-from-description=Z
+	--cover-letter Z
+	EOF
+	test_completion "git send-email --val" <<-\EOF &&
+	--validate Z
+	EOF
+	test_completion "git send-email ma" "main "
+'
+
+test_expect_success 'complete files' '
+	git init tmp && cd tmp &&
+	test_when_finished "cd .. && rm -rf tmp" &&
+
+	echo "expected" > .gitignore &&
+	echo "out" >> .gitignore &&
+	echo "out_sorted" >> .gitignore &&
+
+	git add .gitignore &&
+	test_completion "git commit " ".gitignore" &&
+
+	git commit -m ignore &&
+
+	touch new &&
+	test_completion "git add " "new" &&
+
+	git add new &&
+	git commit -a -m new &&
+	test_completion "git add " "" &&
+
+	git mv new modified &&
+	echo modify > modified &&
+	test_completion "git add " "modified" &&
+
+	mkdir -p some/deep &&
+	touch some/deep/path &&
+	test_completion "git add some/" "some/deep" &&
+	git clean -f some &&
+
+	touch untracked &&
+
+	: TODO .gitignore should not be here &&
+	test_completion "git rm " <<-\EOF &&
+	.gitignore
+	modified
+	EOF
+
+	test_completion "git clean " "untracked" &&
+
+	: TODO .gitignore should not be here &&
+	test_completion "git mv " <<-\EOF &&
+	.gitignore
+	modified
+	EOF
+
+	mkdir dir &&
+	touch dir/file-in-dir &&
+	git add dir/file-in-dir &&
+	git commit -m dir &&
+
+	mkdir untracked-dir &&
+
+	: TODO .gitignore should not be here &&
+	test_completion "git mv modified " <<-\EOF &&
+	.gitignore
+	dir
+	modified
+	untracked
+	untracked-dir
+	EOF
+
+	test_completion "git commit " "modified" &&
+
+	: TODO .gitignore should not be here &&
+	test_completion "git ls-files " <<-\EOF &&
+	.gitignore
+	dir
+	modified
+	EOF
+
+	touch momified &&
+	test_completion "git add mom" "momified"
+'
+
+test_expect_success "simple alias" '
+	test_config alias.co checkout &&
+	test_completion "git co m" <<-\EOF
+	main Z
+	mybranch Z
+	mytag Z
+	EOF
+'
+
+test_expect_success "recursive alias" '
+	test_config alias.co checkout &&
+	test_config alias.cod "co --detached" &&
+	test_completion "git cod m" <<-\EOF
+	main Z
+	mybranch Z
+	mytag Z
+	EOF
+'
+
+test_expect_success "completion uses <cmd> completion for alias: !sh -c 'git <cmd> ...'" '
+	test_config alias.co "!sh -c '"'"'git checkout ...'"'"'" &&
+	test_completion "git co m" <<-\EOF
+	main Z
+	mybranch Z
+	mytag Z
+	EOF
+'
+
+test_expect_success 'completion uses <cmd> completion for alias: !f () { VAR=val git <cmd> ... }' '
+	test_config alias.co "!f () { VAR=val git checkout ... ; } f" &&
+	test_completion "git co m" <<-\EOF
+	main Z
+	mybranch Z
+	mytag Z
+	EOF
+'
+
+test_expect_success 'completion used <cmd> completion for alias: !f() { : git <cmd> ; ... }' '
+	test_config alias.co "!f() { : git checkout ; if ... } f" &&
+	test_completion "git co m" <<-\EOF
+	main Z
+	mybranch Z
+	mytag Z
+	EOF
+'
+
+test_expect_failure 'completion without explicit _git_xxx function' '
+	test_completion "git version --" <<-\EOF
+	--build-options Z
+	--no-build-options Z
+	EOF
+'
+
+test_expect_failure 'complete with tilde expansion' '
+	git init tmp && cd tmp &&
+	test_when_finished "cd .. && rm -rf tmp" &&
+
+	touch ~/tmp/file &&
+
+	test_completion "git add ~/tmp/" "~/tmp/file"
+'
+
+test_expect_success 'setup other remote for remote reference completion' '
+	git remote add other otherrepo &&
+	git fetch other
+'
+
+test_expect_success 'git config - section' '
+	test_completion "git config br" <<-\EOF
+	branch.Z
+	browser.Z
+	EOF
+'
+
+test_expect_success 'git config - section include, includeIf' '
+	test_completion "git config inclu" <<-\EOF
+	include.Z
+	includeIf.Z
+	EOF
+'
+
+test_expect_success 'git config - variable name' '
+	test_completion "git config log.d" <<-\EOF
+	log.date Z
+	log.decorate Z
+	log.diffMerges Z
+	EOF
+'
+
+test_expect_success 'git config - variable name include' '
+	test_completion "git config include.p" <<-\EOF
+	include.path Z
+	EOF
+'
+
+test_expect_success 'git config - value' '
+	test_completion "git config color.pager " <<-\EOF
+	false Z
+	true Z
+	EOF
+'
+
+test_expect_failure 'git -c - section' '
+	test_completion "git -c br" <<-\EOF
+	branch.Z
+	browser.Z
+	EOF
+'
+
+test_expect_failure 'git -c - variable name' '
+	test_completion "git -c log.d" <<-\EOF
+	log.date=Z
+	log.decorate=Z
+	log.diffMerges=Z
+	EOF
+'
+
+test_expect_failure 'git -c - value' '
+	test_completion "git -c color.pager=" <<-\EOF
+	false Z
+	true Z
+	EOF
+'
+
+test_expect_success 'git clone --config= - section' '
+	test_completion "git clone --config=br" <<-\EOF
+	branch.Z
+	browser.Z
+	EOF
+'
+
+test_expect_failure 'git clone --config= - variable name' '
+	test_completion "git clone --config=log.d" <<-\EOF
+	log.date=Z
+	log.decorate=Z
+	log.diffMerges=Z
+	EOF
+'
+
+test_expect_success 'git clone --config= - value' '
+	test_completion "git clone --config=color.pager=" <<-\EOF
+	false Z
+	true Z
+	EOF
+'
+
+test_expect_failure 'options with value' '
+	test_completion "git merge -X diff-algorithm=" <<-\EOF
+
+	EOF
+'
+
+test_done
diff --git a/t/t9904/.gitignore b/t/t9904/.gitignore
new file mode 100644
index 0000000000..f9917e1bf9
--- /dev/null
+++ b/t/t9904/.gitignore
@@ -0,0 +1 @@
+/.zcompdump
diff --git a/t/t9904/.zshrc b/t/t9904/.zshrc
new file mode 100644
index 0000000000..2aec2c9535
--- /dev/null
+++ b/t/t9904/.zshrc
@@ -0,0 +1,51 @@
+setopt zle
+setopt list_rows_first
+
+PS1="<PROMPT>"
+fpath=($ZDOTDIR $fpath)
+LISTMAX=1000
+
+autoload -U compinit && compinit -u
+
+zstyle ':completion:*:*:git:*' script "$SRC_DIR/git-completion.bash"
+zstyle ':completion:*' list-colors "no=<MARK>" "fi=<MARK>" "di=<MARK>" "ec=</MARK>\n" "rc=" "lc=" "sp="
+zstyle ':completion:*' verbose no
+
+zle_complete () {
+	zle list-choices
+	zle kill-whole-line
+	print "<END-CHOICES>"
+}
+zle -N zle_complete
+bindkey "^I" zle_complete
+
+functions[_default]=:
+
+compadd () {
+	local pfx sfx
+	local -a args
+
+	if (( ${@[(I)-a|-d]} )); then
+		builtin compadd -V unsorted "$@"
+	else
+		while (($#)); do
+			case "$1" in
+			-p) pfx="$2" ; shift 2 ;;
+			-S) sfx="$2" ; shift 2 ;;
+			--) args+=($1) ; shift ; break ;;
+			*) args+=("$1") ; shift ;;
+			esac
+		done
+
+		while (($#)); do
+			args+=(${pfx}$1${sfx})
+			shift
+		done
+
+		builtin compadd -V unsorted -S '' "${args[@]}"
+	fi
+}
+
+_git_func () {
+	eval ${words[2,-2]}
+}
diff --git a/t/t9904/_git b/t/t9904/_git
new file mode 120000
index 0000000000..92d0240ac4
--- /dev/null
+++ b/t/t9904/_git
@@ -0,0 +1 @@
+../../contrib/completion/git-completion.zsh
\ No newline at end of file
