Add FNV-1a hash functions (#12502)

tests/integration/fixtures/fnv1a_hash.yaml

@@ -0,0 +1,60 @@
+esphome:
+  name: fnv1a-hash-test
+  platformio_options:
+    build_flags:
+      - "-DDEBUG"
+  on_boot:
+    - lambda: |-
+        using esphome::fnv1a_hash;
+        using esphome::fnv1a_hash_extend;
+
+        // Test empty string (should return offset basis)
+        uint32_t hash_empty = fnv1a_hash("");
+        if (hash_empty == 0x811c9dc5) {
+          ESP_LOGI("FNV1A", "empty PASSED");
+        } else {
+          ESP_LOGE("FNV1A", "empty FAILED: 0x%08x != 0x811c9dc5", hash_empty);
+        }
+
+        // Test known FNV-1a hashes
+        uint32_t hash_hello = fnv1a_hash("hello");
+        if (hash_hello == 0x4f9f2cab) {
+          ESP_LOGI("FNV1A", "known_hello PASSED");
+        } else {
+          ESP_LOGE("FNV1A", "known_hello FAILED: 0x%08x != 0x4f9f2cab", hash_hello);
+        }
+
+        uint32_t hash_helloworld = fnv1a_hash("helloworld");
+        if (hash_helloworld == 0x3b9f5c61) {
+          ESP_LOGI("FNV1A", "known_helloworld PASSED");
+        } else {
+          ESP_LOGE("FNV1A", "known_helloworld FAILED: 0x%08x != 0x3b9f5c61", hash_helloworld);
+        }
+
+        // Test fnv1a_hash_extend consistency
+        uint32_t hash1 = fnv1a_hash("hello");
+        hash1 = fnv1a_hash_extend(hash1, "world");
+        uint32_t hash2 = fnv1a_hash("helloworld");
+
+        if (hash1 == hash2) {
+          ESP_LOGI("FNV1A", "extend PASSED");
+        } else {
+          ESP_LOGE("FNV1A", "extend FAILED: 0x%08x != 0x%08x", hash1, hash2);
+        }
+
+        // Test with std::string
+        std::string str1 = "foo";
+        std::string str2 = "bar";
+        uint32_t hash3 = fnv1a_hash(str1);
+        hash3 = fnv1a_hash_extend(hash3, str2);
+        uint32_t hash4 = fnv1a_hash("foobar");
+
+        if (hash3 == hash4) {
+          ESP_LOGI("FNV1A", "string PASSED");
+        } else {
+          ESP_LOGE("FNV1A", "string FAILED: 0x%08x != 0x%08x", hash3, hash4);
+        }
+
+host:
+api:
+logger:

tests/integration/test_fnv1a_hash.py

@@ -0,0 +1,69 @@
+"""Integration test for FNV-1a hash functions."""
+
+from __future__ import annotations
+
+import asyncio
+import re
+
+import pytest
+
+from .types import APIClientConnectedFactory, RunCompiledFunction
+
+
+@pytest.mark.asyncio
+async def test_fnv1a_hash(
+    yaml_config: str,
+    run_compiled: RunCompiledFunction,
+    api_client_connected: APIClientConnectedFactory,
+) -> None:
+    """Test that FNV-1a hash functions work correctly."""
+
+    test_results = {}
+    all_tests_complete = asyncio.Event()
+    expected_tests = {"empty", "known_hello", "known_helloworld", "extend", "string"}
+
+    def on_log_line(line: str) -> None:
+        """Capture log lines with test results."""
+        # Strip ANSI escape codes
+        clean_line = re.sub(r"\x1b\[[0-9;]*m", "", line)
+        # Look for our test result messages
+        # Format: "[timestamp][level][FNV1A:line]: test_name PASSED"
+        match = re.search(r"\[FNV1A:\d+\]:\s+(\w+)\s+(PASSED|FAILED)", clean_line)
+        if match:
+            test_name = match.group(1)
+            result = match.group(2)
+            test_results[test_name] = result
+            if set(test_results.keys()) >= expected_tests:
+                all_tests_complete.set()
+
+    async with (
+        run_compiled(yaml_config, line_callback=on_log_line),
+        api_client_connected() as client,
+    ):
+        device_info = await client.device_info()
+        assert device_info is not None
+        assert device_info.name == "fnv1a-hash-test"
+
+        # Wait for all tests to complete or timeout
+        try:
+            await asyncio.wait_for(all_tests_complete.wait(), timeout=2.0)
+        except TimeoutError:
+            pytest.fail(f"Tests timed out. Got results for: {set(test_results.keys())}")
+
+        # Verify all tests passed
+        assert "empty" in test_results, "empty string test not found"
+        assert test_results["empty"] == "PASSED", "empty string test failed"
+
+        assert "known_hello" in test_results, "known_hello test not found"
+        assert test_results["known_hello"] == "PASSED", "known_hello test failed"
+
+        assert "known_helloworld" in test_results, "known_helloworld test not found"
+        assert test_results["known_helloworld"] == "PASSED", (
+            "known_helloworld test failed"
+        )
+
+        assert "extend" in test_results, "fnv1a_hash_extend test not found"
+        assert test_results["extend"] == "PASSED", "fnv1a_hash_extend test failed"
+
+        assert "string" in test_results, "std::string test not found"
+        assert test_results["string"] == "PASSED", "std::string test failed"