Initial commit

tests/test_messages.py

@@ -0,0 +1,40 @@
+from meshbot.messages import trim_to_bytes
+
+
+def test_short_ascii_passthrough():
+    assert trim_to_bytes("hello", 184) == "hello"
+
+
+def test_exact_fit_passthrough():
+    s = "a" * 184
+    assert trim_to_bytes(s, 184) == s
+
+
+def test_long_ascii_clean_cut():
+    s = "x" * 200
+    out = trim_to_bytes(s, 184)
+    assert len(out.encode("utf-8")) == 184
+    assert out == "x" * 184
+
+
+def test_emoji_does_not_split():
+    # Each 🎉 is 4 UTF-8 bytes. Limit of 5 must keep just one emoji (4 bytes), not 5.
+    out = trim_to_bytes("🎉🎉", 5)
+    assert out == "🎉"
+    assert len(out.encode("utf-8")) == 4
+
+
+def test_multibyte_at_boundary():
+    # "ä" is 2 bytes in UTF-8. With a 3-byte budget for "aä" (3 bytes total), we keep both.
+    assert trim_to_bytes("aä", 3) == "aä"
+    # With a 2-byte budget we can only keep the leading "a".
+    assert trim_to_bytes("aä", 2) == "a"
+
+
+def test_zero_or_negative_max_bytes():
+    assert trim_to_bytes("anything", 0) == ""
+    assert trim_to_bytes("anything", -1) == ""
+
+
+def test_empty_input():
+    assert trim_to_bytes("", 184) == ""