[bk72xx_ble] Scan primitives and main-task scan report queue (#17802)

Co-authored-by: J. Nick Koston <nick@koston.org>

tests/components/core/test_lock_free_queue.cpp

@@ -0,0 +1,96 @@
+// Exercises the no-atomics LockFreeQueue implementation (PlainAtomic indices —
+// the path used on cores without atomic RMW instructions, currently BK72xx).
+// The define is forced before the include so this TU deterministically compiles
+// that path regardless of the host's default thread model; no other test TU
+// instantiates this template, so the differing definition is confined here.
+#define ESPHOME_THREAD_MULTI_NO_ATOMICS
+#include "esphome/core/lock_free_queue.h"
+
+#include <gtest/gtest.h>
+
+namespace esphome::core::testing {
+
+TEST(LockFreeQueueNoAtomics, EmptyPopReturnsNull) {
+  esphome::LockFreeQueue<int, 4> q;
+  EXPECT_EQ(q.pop(), nullptr);
+  EXPECT_TRUE(q.empty());
+  EXPECT_FALSE(q.full());
+  EXPECT_EQ(q.size(), 0u);
+}
+
+TEST(LockFreeQueueNoAtomics, FifoOrder) {
+  esphome::LockFreeQueue<int, 4> q;
+  int a = 1, b = 2, c = 3;
+  EXPECT_TRUE(q.push(&a));
+  EXPECT_TRUE(q.push(&b));
+  EXPECT_TRUE(q.push(&c));
+  EXPECT_EQ(q.size(), 3u);
+  EXPECT_EQ(q.pop(), &a);
+  EXPECT_EQ(q.pop(), &b);
+  EXPECT_EQ(q.pop(), &c);
+  EXPECT_EQ(q.pop(), nullptr);
+}
+
+TEST(LockFreeQueueNoAtomics, CapacityIsSizeMinusOne) {
+  esphome::LockFreeQueue<int, 4> q;
+  int v[4] = {0, 1, 2, 3};
+  EXPECT_TRUE(q.push(&v[0]));
+  EXPECT_TRUE(q.push(&v[1]));
+  EXPECT_TRUE(q.push(&v[2]));
+  EXPECT_TRUE(q.full());
+  // Ring reserves one slot: the SIZEth push fails and is counted as dropped.
+  EXPECT_FALSE(q.push(&v[3]));
+  EXPECT_EQ(q.get_and_reset_dropped_count(), 1u);
+  EXPECT_EQ(q.get_and_reset_dropped_count(), 0u);  // reset is sticky
+}
+
+TEST(LockFreeQueueNoAtomics, NullPushRejected) {
+  esphome::LockFreeQueue<int, 4> q;
+  EXPECT_FALSE(q.push(nullptr));
+  EXPECT_TRUE(q.empty());
+}
+
+TEST(LockFreeQueueNoAtomics, WrapAround) {
+  esphome::LockFreeQueue<int, 4> q;
+  int v[3] = {10, 20, 30};
+  // Cycle several times the ring size to cross the wrap boundary repeatedly.
+  for (int cycle = 0; cycle < 10; cycle++) {
+    for (auto &value : v)
+      ASSERT_TRUE(q.push(&value));
+    EXPECT_TRUE(q.full());
+    for (auto &value : v)
+      ASSERT_EQ(q.pop(), &value);
+    EXPECT_TRUE(q.empty());
+  }
+  EXPECT_EQ(q.get_and_reset_dropped_count(), 0u);
+}
+
+TEST(LockFreeQueueNoAtomics, IncrementDroppedCount) {
+  esphome::LockFreeQueue<int, 4> q;
+  // Producer-side external drop accounting (pool exhausted before push).
+  q.increment_dropped_count();
+  q.increment_dropped_count();
+  EXPECT_EQ(q.get_and_reset_dropped_count(), 2u);
+}
+
+TEST(LockFreeQueueNoAtomics, InterleavedPushPop) {
+  esphome::LockFreeQueue<int, 8> q;
+  int v[64];
+  int popped = 0;
+  for (int i = 0; i < 64; i++) {
+    v[i] = i;
+    ASSERT_TRUE(q.push(&v[i]));
+    if (i % 2 == 1) {
+      int *first = q.pop();
+      ASSERT_NE(first, nullptr);
+      EXPECT_EQ(*first, popped++);
+      int *second = q.pop();
+      ASSERT_NE(second, nullptr);
+      EXPECT_EQ(*second, popped++);
+    }
+  }
+  EXPECT_TRUE(q.empty());
+  EXPECT_EQ(popped, 64);
+}
+
+}  // namespace esphome::core::testing