t3701-add-interactive: test add_i_show_help()

Add test to t3701-add-interactive to verify that add_i_show_help()
outputs expected content.
Also, add it before changing git-add--interactive.perl's help_cmd
to demonstrate that there are no changes introduced by the
conversion to C.
Prefix git add -i call with GIT_PAGER_IN_USE=true TERM=vt100
to force colored output on Windows.

Signed-off-by: Slavica Djukic <[email protected]>

Author: slavicaDj

t/t3701-add-interactive.sh

@@ -639,4 +639,28 @@ test_expect_success 'add -p patch editing works with pathological context lines'
 	test_cmp expected-2 actual
 '
 
+test_expect_success 'show help from add--helper' '
+	git reset --hard &&
+	cat >expect <<-\EOF &&
+
+	<BOLD>*** Commands ***<RESET>
+	  1: <BOLD;BLUE>s<RESET>tatus	  2: <BOLD;BLUE>u<RESET>pdate	  3: <BOLD;BLUE>r<RESET>evert	  4: <BOLD;BLUE>a<RESET>dd untracked
+	  5: <BOLD;BLUE>p<RESET>atch	  6: <BOLD;BLUE>d<RESET>iff	  7: <BOLD;BLUE>q<RESET>uit	  8: <BOLD;BLUE>h<RESET>elp
+	<BOLD;BLUE>What now<RESET>> <BOLD;RED>status        - show paths with changes<RESET>
+	<BOLD;RED>update        - add working tree state to the staged set of changes<RESET>
+	<BOLD;RED>revert        - revert staged set of changes back to the HEAD version<RESET>
+	<BOLD;RED>patch         - pick hunks and update selectively<RESET>
+	<BOLD;RED>diff          - view diff between HEAD and index<RESET>
+	<BOLD;RED>add untracked - add contents of untracked files to the staged set of changes<RESET>
+	<BOLD>*** Commands ***<RESET>
+	  1: <BOLD;BLUE>s<RESET>tatus	  2: <BOLD;BLUE>u<RESET>pdate	  3: <BOLD;BLUE>r<RESET>evert	  4: <BOLD;BLUE>a<RESET>dd untracked
+	  5: <BOLD;BLUE>p<RESET>atch	  6: <BOLD;BLUE>d<RESET>iff	  7: <BOLD;BLUE>q<RESET>uit	  8: <BOLD;BLUE>h<RESET>elp
+	<BOLD;BLUE>What now<RESET>> 
+	Bye.
+	EOF
+	test_write_lines h | GIT_PAGER_IN_USE=true TERM=vt100 git add -i >actual.colored &&
+	test_decode_color <actual.colored >actual &&
+	test_i18ncmp expect actual
+'
+
 test_done