Add Unit Tests For Hostapd AIDL

This should allow for testing hostapd AIDL implementation code

Bug: 361651437
Test: libhostapd_aidl_bp_unittest
Change-Id: If67b84ba4a2753b43987b2d79833c9616df73cf9
diff --git a/hostapd/aidl/tests/unittests.cpp b/hostapd/aidl/tests/unittests.cpp
new file mode 100644
index 0000000..900f043
--- /dev/null
+++ b/hostapd/aidl/tests/unittests.cpp
@@ -0,0 +1,80 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <cstring>
+
+#include <gtest/gtest.h>
+#include "../hostapd.cpp"
+
+namespace aidl::android::hardware::wifi::hostapd {
+
+/**
+ * Null hostapd_data* and null mac address (u8*)
+ * There's an || check on these that should return nullopt
+ */
+TEST(getStaInfoByMacAddrTest, NullArguments) {
+	EXPECT_EQ(std::nullopt, getStaInfoByMacAddr(nullptr, nullptr));
+}
+
+
+/**
+ * We pass valid arguments to get past the nullptr check, but hostapd_data->sta_list is nullptr.
+ * Don't loop through the sta_info* list, just return nullopt.
+ */
+TEST(getStaInfoByMacAddrTest, NullStaList) {
+	struct hostapd_data iface_hapd = {};
+	u8 mac_addr[] = {0xDE, 0xAD, 0xBE, 0xEF, 0xD0, 0x0D};
+	EXPECT_EQ(std::nullopt, getStaInfoByMacAddr(&iface_hapd, mac_addr));
+}
+
+/**
+ * Mac doesn't match, and we hit the end of the sta_info list.
+ * Don't run over the end of the list and return nullopt.
+ */
+TEST(getStaInfoByMacAddrTest, NoMatchingMac) {
+	struct hostapd_data iface_hapd = {};
+	struct sta_info sta0 = {};
+	struct sta_info sta1 = {};
+	struct sta_info sta2 = {};
+	iface_hapd.sta_list = &sta0;
+	sta0.next = &sta1;
+	sta1.next = &sta2;
+	u8 mac_addr[] = {0xDE, 0xAD, 0xBE, 0xEF, 0xD0, 0x0D};
+	EXPECT_EQ(std::nullopt, getStaInfoByMacAddr(&iface_hapd, mac_addr));
+}
+
+/**
+ * There is a matching address and we return it.
+ */
+TEST(getStaInfoByMacAddr, MatchingMac) {
+	struct hostapd_data iface_hapd = {};
+	struct sta_info sta0 = {};
+	struct sta_info sta1 = {};
+	struct sta_info sta2 = {};
+	iface_hapd.sta_list = &sta0;
+	sta0.next = &sta1;
+	sta1.next = &sta2;
+	u8 sta0_addr[] = {0xDE, 0xAD, 0xBE, 0xEF, 0xD0, 0x0C};  // off by 1 bit
+	std::memcpy(sta0.addr, sta0_addr, ETH_ALEN);
+	u8 sta1_addr[] = {0xDE, 0xAD, 0xBE, 0xEF, 0xD0, 0x0D};
+	std::memcpy(sta1.addr, sta1_addr, ETH_ALEN);
+	u8 mac_addr[] = {0xDE, 0xAD, 0xBE, 0xEF, 0xD0, 0x0D};
+	auto sta_ptr_optional = getStaInfoByMacAddr(&iface_hapd, mac_addr);
+	EXPECT_TRUE(sta_ptr_optional.has_value());
+	EXPECT_EQ(0, std::memcmp(sta_ptr_optional.value()->addr, sta1_addr, ETH_ALEN));
+}
+
+}  // namespace aidl::android::hardware::wifi::hostapd