test-tool: bloom: generate_filter for multiple string?

["Đoàn Trần Công Danh" <congdanhqx@gmail.com>]

Hello,

I'm reading the code for Bloom Filter to see if arXiv:2012.00472
could be an improvement.

I'm not sure if I'm missing something or it's our test-bloom generate_filter
doesn't really support testing for multiple inputs.

If I understand correctly, we should either:
* allocate more entry for inputs; or
* abort if argc != 3

diff --git a/t/helper/test-bloom.c b/t/helper/test-bloom.c
index 46e97b04eb..1026facc59 100644
--- a/t/helper/test-bloom.c
+++ b/t/helper/test-bloom.c
@@ -68,12 +68,14 @@ int cmd__bloom(int argc, const char **argv)
 	if (!strcmp(argv[1], "generate_filter")) {
 		struct bloom_filter filter;
 		int i = 2;
-		filter.len =  (settings.bits_per_entry + BITS_PER_WORD - 1) / BITS_PER_WORD;
-		filter.data = xcalloc(filter.len, sizeof(unsigned char));
 
 		if (argc - 1 < i)
 			usage(bloom_usage);
 
+		filter.len = (settings.bits_per_entry * (argc - 2) + BITS_PER_WORD - 1)
+			/ BITS_PER_WORD;
+		filter.data = xcalloc(filter.len, sizeof(unsigned char));
+
 		while (argv[i]) {
 			add_string_to_filter(argv[i], &filter);
 			i++;
diff --git a/t/t0095-bloom.sh b/t/t0095-bloom.sh
index 7e4ab1795f..6d83927c86 100755
--- a/t/t0095-bloom.sh
+++ b/t/t0095-bloom.sh
@@ -67,6 +67,17 @@ test_expect_success 'compute bloom key for test string 2' '
 	test_cmp expect actual
 '
 
+test_expect_success 'compute bloom key for multiple string' '
+	cat >expect <<-\EOF &&
+	Hashes:0xb270de9b|0x1bb6f26e|0x84fd0641|0xee431a14|0x57892de7|0xc0cf41ba|0x2a15558d|
+	Hashes:0x20ab385b|0xf5237fe2|0xc99bc769|0x9e140ef0|0x728c5677|0x47049dfe|0x1b7ce585|
+	Filter_Length:3
+	Filter_Data:45|ba|ac|
+	EOF
+	test-tool bloom generate_filter "Hello world!" file.txt >actual &&
+	test_cmp expect actual
+'
+
 test_expect_success 'get bloom filters for commit with no changes' '
 	git init &&
 	git commit --allow-empty -m "c0" &&
-- 
Danh