class GloballyOrderedRegion

An MMIO range that responds to a list of pre-determined memory accesses.

GloballyOrderedRegion enforces a global ordering on all accesses to the mocked MMIO

range. This is stricter than Region, which accepts any interleaving of the access

lists specified at the register level. So, GloballyOrderedRegion results in more brittle

mocks, and should only be used when there is a single acceptable access ordering.

Example usage:

constexpr static size_t kMmioRegionSize = 0x4000;

GloballyOrderedRegion region_{kMmioRegionSize, GloballyOrderedRegion::Size::k32};

fdf::MmioBuffer buffer_{region_.GetMmioBuffer()};

// Expect a 32-bit read at 0x1000, the read will return 0x12345678.

region_.Expect({.address = 0x1000, .value = 0x12345678});

// Expect a 32-bit write of 0x87654321 at 0x1002

region_.Expect({.address = 0x1002, .value = 0x87654321, .write = true});

// Test polling for a ready flag at 0x1004.

region_.Expect(GloballyOrderedRegion::AccessList({

{.address = 0x1004, .value = 0x0},

{.address = 0x1004, .value = 0x0},

{.address = 0x1004, .value = 0x0},

{.address = 0x1004, .value = 0x1},

}));

// This could go in TearDown().

region_.CheckAllAccessesReplayed();

The following practices are not required, but are consistent with the

recommendation of keeping testing logic simple:

* Expect() calls should be at the beginning of the test case, before

executing the code that accesses the MMIO region.

* A test's expectations should be grouped in a single Expect() call. In rare

cases, multiple cases and conditional logic may improve readability.

* Expect() should not be called concurrently from multiple threads.

GloballyOrderedRegion instances are 100% thread-safe because all MMIO accesses to the region are

serialized using a mutex.