Write unit tests for this class
```cpp
class queue {
 public:
 bool push(int val);
 std::optional pop();
 private:
 int buffer[64];
};
```
To write unit tests for the `queue` class, we need to ensure that we cover various scenarios such as pushing elements to the queue, popping elements from the queue, and handling edge cases such as popping from an empty queue. Below is an example of how you might write unit tests for this class using the Google Test framework, which is a popular C++ testing library.

First, ensure you have Google Test set up in your project. Then, you can create a test file (e.g., `queue_test.cpp`) and include the necessary headers and your queue class definition.

Here's how you could implement the unit tests:

```cpp
#include <gtest/gtest.h>
#include <optional>
#include "queue.h" // Include your queue class header

class QueueTest : public ::testing::Test {
protected:
    queue q; // Instance of the queue class for testing
};

// Test pushing elements to the queue
TEST_F(QueueTest, PushElements) {
    EXPECT_TRUE(q.push(1));
    EXPECT_TRUE(q.push(2));
    EXPECT_TRUE(q.push(3));
}

// Test popping elements from the queue
TEST_F(QueueTest, PopElements) {
    q.push(1);
    q.push(2);
    
    std::optional<int> val = q.pop();
    EXPECT_TRUE(val.has_value());
    EXPECT_EQ(val.value(), 1); // Assuming FIFO, 1 should be popped first

    val = q.pop();
    EXPECT_TRUE(val.has_value());

 Here is an example of how you could write unit tests for the `queue` class in C++ using Google Test framework:

```cpp
#include "gtest/gtest.h"
#include "queue.h"

TEST(QueueTest, PushPopTest) {
    queue q;

    EXPECT_TRUE(q.push(1));
    EXPECT_TRUE(q.push(2));
    EXPECT_TRUE(q.push(3));

    EXPECT_EQ(q.pop(), 1);
    EXPECT_EQ(q.pop(), 2);

    EXPECT_TRUE(q.push(4));
    EXPECT_EQ(q.pop(), 3);
    EXPECT_EQ(q.pop(), 4);
}

TEST(QueueTest, EmptyPopTest) {
    queue q;

    EXPECT_FALSE(q.pop());
}

TEST(QueueTest, FullPushTest) {
    queue q;

    for (int i = 0; i < 64; i++) {
        EXPECT_TRUE(q.push(i));
    }

    EXPECT_FALSE(q.push(65));
}
```
In the first test case, `PushPopTest`, we are testing that the `push` and `pop` methods