test: add a bunch of strv helpers

Taken from libinput

Part-of: <https://gitlab.freedesktop.org/libinput/libei/-/merge_requests/337>

src/util-strings.c

@@ -220,6 +220,86 @@ strreplace(const char *string, const char *separator, const char *replacement)
 	return tmp;
 }
 
+size_t
+strv_len(char **strv)
+{
+	if (!strv)
+		return 0;
+
+	size_t size = 1;
+	while (*strv) {
+		size++;
+		strv++;
+	}
+	return size;
+}
+
+char **
+strv_append_take(char **strv, char **str)
+{
+	if (str && *str) {
+		size_t len = max(strv_len(strv) + 1, 2);
+
+		char **s = realloc(strv, len * sizeof(*strv));
+		if (!s)
+			abort();
+		s[len - 1] = NULL;
+		s[len - 2] = *str;
+		*str = NULL;
+		return s;
+	} else {
+		return strv;
+	}
+}
+
+char **
+strv_append_strdup(char **strv, const char *str)
+{
+	char *dup = xstrdup(str);
+	return strv_append_take(strv, &dup);
+}
+
+bool
+strv_find(char **strv, const char *needle, size_t *index_out)
+{
+	if (!strv)
+		return false;
+
+	size_t index = 0;
+	char **s = strv;
+	while (*s != NULL) {
+		if (streq(*s, needle)) {
+			if (index_out)
+				*index_out = index;
+			return true;
+		}
+		s++;
+		index++;
+	}
+
+	return false;
+}
+
+bool
+strv_find_substring(char **strv, const char *needle, size_t *index_out)
+{
+	if (!strv || !needle)
+		return false;
+
+	size_t index = 0;
+	char **s = strv;
+	while (*s != NULL) {
+		if (strstr(*s, needle)) {
+			if (index_out)
+				*index_out = index;
+			return true;
+		}
+		s++;
+		index++;
+	}
+
+	return false;
+}
 
 char **
 strv_from_mem(const uint8_t *buffer, size_t sz, size_t stride)

src/util-strings.h

@@ -254,9 +254,16 @@ xatod(const char *str, double *val)
 	return true;
 }
 
+size_t strv_len(char **strv);
+/* Takes ownership of the string and appends it to strv, s is set to NULL */
+char **strv_append_take(char **strv, char **s);
+char **strv_append_strdup(char **strv, const char *s);
 char **strv_from_string(const char *string, const char *separator);
 char *strv_join(char **strv, const char *separator);
 
+bool strv_find(char **strv, const char *needle, size_t *index_out);
+bool strv_find_substring(char **strv, const char *needle, size_t *index_out);
+
 static inline void
 strv_free(char **strv) {
 	char **s = strv;