t7006: add tests for how git branch paginates

The next couple of commits will change how `git branch` handles
`pager.branch`, similar to how de121ffe5 (tag: respect `pager.tag` in
list-mode only, 2017-08-02) and ff1e72483 (tag: change default of
`pager.tag` to "on", 2017-08-02) changed `git tag`.

Add tests in this area to make sure that we don't regress and so that
the upcoming commits can be made clearer by adapting the tests. Add some
tests for `--list` (implied), one for `--edit-description`, and one for
`--set-upstream-to` as a representative of "something other than the
first two".

In particular, use `test_expect_failure` to document that we currently
respect the pager-configuration with `--edit-description`. The current
behavior is buggy since the pager interferes with the editor and makes
the end result completely broken. See also b3ee740c8 (t7006: add tests
for how git tag paginates, 2017-08-02).

Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t7006-pager.sh

@@ -214,6 +214,44 @@ test_expect_success TTY 'git tag as alias respects pager.tag with -l' '
 	! test -e paginated.out
 '
 
+test_expect_success TTY 'git branch defaults to not paging' '
+	rm -f paginated.out &&
+	test_terminal git branch &&
+	! test -e paginated.out
+'
+
+test_expect_success TTY 'git branch respects pager.branch' '
+	rm -f paginated.out &&
+	test_terminal git -c pager.branch branch &&
+	test -e paginated.out
+'
+
+test_expect_success TTY 'git branch respects --no-pager' '
+	rm -f paginated.out &&
+	test_terminal git -c pager.branch --no-pager branch &&
+	! test -e paginated.out
+'
+
+test_expect_failure TTY 'git branch --edit-description ignores pager.branch' '
+	rm -f paginated.out editor.used &&
+	write_script editor <<-\EOF &&
+		echo "New description" >"$1"
+		touch editor.used
+	EOF
+	EDITOR=./editor test_terminal git -c pager.branch branch --edit-description &&
+	! test -e paginated.out &&
+	test -e editor.used
+'
+
+test_expect_success TTY 'git branch --set-upstream-to respects pager.branch' '
+	rm -f paginated.out &&
+	git branch other &&
+	test_when_finished "git branch -D other" &&
+	test_terminal git -c pager.branch branch --set-upstream-to=other &&
+	test_when_finished "git branch --unset-upstream" &&
+	test -e paginated.out
+'
+
 # A colored commit log will begin with an appropriate ANSI escape
 # for the first color; the text "commit" comes later.
 colorful() {