Chore: Rework examples for thorough extension testing

1 files changed, 86 insertions, 0 deletions

diff --git a/examples/test-suite/src/strings.zig b/examples/test-suite/src/strings.zig
new file mode 100644
index 0000000..ba53f8c
--- /dev/null
+++ b/examples/test-suite/src/strings.zig
@@ -0,0 +1,86 @@
+const std = @import("std");
+
+/// Trim leading and trailing ASCII whitespace.
+pub fn trim(s: []const u8) []const u8 {
+    return std.mem.trim(u8, s, " \t\r\n");
+}
+
+/// Count non-overlapping occurrences of `needle` in `haystack`.
+pub fn countOccurrences(haystack: []const u8, needle: []const u8) usize {
+    if (needle.len == 0) return 0;
+    var count: usize = 0;
+    var i: usize = 0;
+    while (i + needle.len <= haystack.len) {
+        if (std.mem.eql(u8, haystack[i .. i + needle.len], needle)) {
+            count += 1;
+            i += needle.len;
+        } else {
+            i += 1;
+        }
+    }
+    return count;
+}
+
+/// Reverse a string byte-by-byte (ASCII safe; not grapheme-safe).
+pub fn reverseAlloc(allocator: std.mem.Allocator, s: []const u8) ![]u8 {
+    const result = try allocator.alloc(u8, s.len);
+    for (s, 0..) |byte, i| result[s.len - 1 - i] = byte;
+    return result;
+}
+
+/// Returns true if `s` starts with `prefix`.
+pub fn startsWith(s: []const u8, prefix: []const u8) bool {
+    return std.mem.startsWith(u8, s, prefix);
+}
+
+// ── Tests with "strings: " prefix ────────────────────────────────────────────
+// Run all:           zig build test
+// Run strings only:  zig build test -- --test-filter "strings:"
+
+test "strings: trim removes spaces" {
+    try std.testing.expectEqualStrings("hello", trim("  hello  "));
+}
+
+test "strings: trim handles empty and whitespace-only" {
+    try std.testing.expectEqualStrings("", trim(""));
+    try std.testing.expectEqualStrings("", trim("   \t\n"));
+}
+
+test "strings: trim preserves inner whitespace" {
+    try std.testing.expectEqualStrings("hello world", trim("  hello world  "));
+}
+
+test "strings: countOccurrences basic" {
+    try std.testing.expectEqual(@as(usize, 3), countOccurrences("abcabcabc", "abc"));
+}
+
+test "strings: countOccurrences empty needle" {
+    try std.testing.expectEqual(@as(usize, 0), countOccurrences("hello", ""));
+}
+
+test "strings: countOccurrences no match" {
+    try std.testing.expectEqual(@as(usize, 0), countOccurrences("hello", "xyz"));
+}
+
+test "strings: countOccurrences overlapping boundary" {
+    // Non-overlapping: "aa" in "aaaa" = 2
+    try std.testing.expectEqual(@as(usize, 2), countOccurrences("aaaa", "aa"));
+}
+
+test "strings: reverseAlloc" {
+    const reversed = try reverseAlloc(std.testing.allocator, "hello");
+    defer std.testing.allocator.free(reversed);
+    try std.testing.expectEqualStrings("olleh", reversed);
+}
+
+test "strings: reverseAlloc empty" {
+    const reversed = try reverseAlloc(std.testing.allocator, "");
+    defer std.testing.allocator.free(reversed);
+    try std.testing.expectEqualStrings("", reversed);
+}
+
+test "strings: startsWith" {
+    try std.testing.expect(startsWith("hello world", "hello"));
+    try std.testing.expect(!startsWith("hello world", "world"));
+    try std.testing.expect(startsWith("abc", ""));
+}