From 07d0667d067d49a1834f0503bb48a835972ee93a Mon Sep 17 00:00:00 2001
From: "google-labs-jules[bot]"
 <161369871+google-labs-jules[bot]@users.noreply.github.com>
Date: Wed, 14 Jan 2026 08:22:32 +0000
Subject: [PATCH] [AI] Expand Test Coverage - eldritch-core/strings

Added comprehensive tests for string methods including splitlines, title, format, codepoints, and partitioning edge cases. Verified stability with 20 test runs.
---
 .../tests/strings_extended_coverage.rs        | 161 ++++++++++++++++++
 1 file changed, 161 insertions(+)
 create mode 100644 implants/lib/eldritchv2/eldritch-core/tests/strings_extended_coverage.rs

diff --git a/implants/lib/eldritchv2/eldritch-core/tests/strings_extended_coverage.rs b/implants/lib/eldritchv2/eldritch-core/tests/strings_extended_coverage.rs
new file mode 100644
index 000000000..a4fb3838a
--- /dev/null
+++ b/implants/lib/eldritchv2/eldritch-core/tests/strings_extended_coverage.rs
@@ -0,0 +1,161 @@
+mod assert;
+
+#[test]
+fn test_splitlines_extended() {
+    assert::pass(
+        r#"
+        # Default behavior (keepends=False)
+        assert_eq("a\nb\nc".splitlines(), ["a", "b", "c"])
+        assert_eq("a\nb\nc\n".splitlines(), ["a", "b", "c"])
+
+        # With keepends=True
+        assert_eq("a\nb".splitlines(True), ["a\n", "b"])
+        assert_eq("a\nb\n".splitlines(True), ["a\n", "b\n"])
+
+        # With keepends=False explicit
+        assert_eq("a\nb".splitlines(False), ["a", "b"])
+
+        # Empty string
+        assert_eq("".splitlines(), [])
+        assert_eq("".splitlines(True), [])
+
+        # Mixed newlines (splitlines usually handles \n, \r\n, \r)
+        # Note: Current implementation uses s.split_inclusive('\n') or s.lines()
+        # s.lines() handles \n and \r\n.
+        assert_eq("a\r\nb".splitlines(), ["a", "b"])
+    "#,
+    );
+}
+
+#[test]
+fn test_title_extended() {
+    assert::pass(
+        r#"
+        assert_eq("hello world".title(), "Hello World")
+        assert_eq("HELLO WORLD".title(), "Hello World")
+        assert_eq("HeLLo WoRLd".title(), "Hello World")
+
+        # Non-alphabetic separators
+        assert_eq("hello-world".title(), "Hello-World")
+        assert_eq("hello'world".title(), "Hello'World")
+        assert_eq("1st place".title(), "1St Place") # Python's title() behavior: 1St (since '1' is not alphabetic, 's' is start of new word)
+
+        # Empty
+        assert_eq("".title(), "")
+    "#,
+    );
+}
+
+#[test]
+fn test_strip_variants_extended() {
+    assert::pass(
+        r#"
+        # lstrip/rstrip/strip with args
+        assert_eq("www.example.com".lstrip("cmwz."), "example.com")
+        assert_eq("www.example.com".rstrip("omz."), "www.example.c")
+        assert_eq("www.example.com".strip("w.moc"), "example")
+
+        # Order of chars in arg shouldn't matter
+        assert_eq("abc".strip("cba"), "")
+
+        # Empty args
+        assert_eq("  abc  ".strip(""), "  abc  ") # Strips nothing if chars is empty
+
+        # Empty string
+        assert_eq("".strip(), "")
+        assert_eq("".lstrip("a"), "")
+    "#,
+    );
+}
+
+#[test]
+fn test_remove_prefix_suffix_extended() {
+    assert::pass(
+        r#"
+        s = "TestString"
+        assert_eq(s.removeprefix("Test"), "String")
+        assert_eq(s.removeprefix("NonExistent"), "TestString")
+        assert_eq(s.removeprefix(""), "TestString")
+        assert_eq(s.removeprefix(s), "")
+
+        assert_eq(s.removesuffix("String"), "Test")
+        assert_eq(s.removesuffix("NonExistent"), "TestString")
+        assert_eq(s.removesuffix(""), "TestString")
+        assert_eq(s.removesuffix(s), "")
+    "#,
+    );
+}
+
+#[test]
+fn test_format_extended() {
+    assert::pass(
+        r#"
+        # Basic
+        assert_eq("{} {}".format("a", "b"), "a b")
+
+        # Extra args ignored (Python does this, verify impl)
+        # Impl: uses arg_idx, ignores extra
+        assert_eq("{}".format("a", "b"), "a")
+
+        # Not enough args -> IndexError handled below
+
+        # No placeholders
+        assert_eq("no placeholders".format("a"), "no placeholders")
+
+        # Unclosed braces - verify behavior (impl dumps chars)
+        assert_eq("{".format("a"), "{")
+        assert_eq("}".format("a"), "}")
+    "#,
+    );
+
+    assert::fail("'{}'.format()", "IndexError");
+}
+
+#[test]
+fn test_partition_extended() {
+    assert::pass(
+        r#"
+        # Sep found
+        assert_eq("a.b".partition("."), ("a", ".", "b"))
+        assert_eq("a.b".rpartition("."), ("a", ".", "b"))
+
+        # Sep at start
+        assert_eq(".b".partition("."), ("", ".", "b"))
+        assert_eq(".b".rpartition("."), ("", ".", "b"))
+
+        # Sep at end
+        assert_eq("a.".partition("."), ("a", ".", ""))
+        assert_eq("a.".rpartition("."), ("a", ".", ""))
+
+        # Sep not found
+        assert_eq("abc".partition("."), ("abc", "", ""))
+        assert_eq("abc".rpartition("."), ("", "", "abc"))
+
+        # Empty string
+        assert_eq("".partition("."), ("", "", ""))
+
+        # Multiple separators
+        assert_eq("a.b.c".partition("."), ("a", ".", "b.c"))
+        assert_eq("a.b.c".rpartition("."), ("a.b", ".", "c"))
+    "#,
+    );
+}
+
+#[test]
+fn test_unicode_extended() {
+    assert::pass(
+        r#"
+        s = "🔥"
+        assert_eq(len(s), 4) # len() returns byte length in Eldritch
+
+        assert_eq(s.codepoints(), [128293])
+        assert_eq(s.elems(), ["🔥"])
+
+        s2 = "a🔥b"
+        assert_eq(s2.elems(), ["a", "🔥", "b"])
+
+        # Reverse string with unicode
+        assert_eq(s2[::-1], "b🔥a")
+    "#,
+    );
+}