test: validate missing encoding in to_string (#606)

* test: validate missing encoding in to_string

* fix: update encoding set to represent reality

* fix formatting

Author: anonrig

include/ada/character_sets-inl.h

@@ -458,7 +458,7 @@ constexpr uint8_t WWW_FORM_URLENCODED_PERCENT_ENCODE[32] = {
     // 20     21     22     23     24     25     26     27
     0x00 | 0x02 | 0x04 | 0x08 | 0x10 | 0x20 | 0x40 | 0x80,
     // 28     29     2A     2B     2C     2D     2E     2F
-    0x01 | 0x02 | 0x00 | 0x08 | 0x10 | 0x00 | 0x00 | 0x00,
+    0x01 | 0x02 | 0x00 | 0x08 | 0x10 | 0x00 | 0x00 | 0x80,
     // 30     31     32     33     34     35     36     37
     0x00 | 0x00 | 0x00 | 0x00 | 0x00 | 0x00 | 0x00 | 0x00,
     // 38     39     3A     3B     3C     3D     3E     3F

tests/url_search_params.cpp

@@ -219,3 +219,16 @@ TEST(url_search_params, iterators) {
 
   SUCCEED();
 }
+
+// https://github.com/cloudflare/workerd/issues/1777
+TEST(url_search_params, test_to_string_encoding) {
+  auto search_params =
+      ada::url_search_params("q1=foo&q2=foo+bar&q3=foo bar&q4=foo/bar");
+  ASSERT_EQ(search_params.get("q1").value(), "foo");
+  ASSERT_EQ(search_params.get("q2").value(), "foo bar");
+  ASSERT_EQ(search_params.get("q3").value(), "foo bar");
+  ASSERT_EQ(search_params.get("q4").value(), "foo/bar");
+  ASSERT_EQ(search_params.to_string(),
+            "q1=foo&q2=foo+bar&q3=foo+bar&q4=foo%2Fbar");
+  SUCCEED();
+}