S24.02: Adopt CALLED_FUNCTION test macro and standardise *CallCount naming #321

Overview

Replace ad-hoc call-count assertions across the test base with a small set
of named macros, and standardise the <name>CallCount variable/getter
naming so the macros work uniformly. Pure test refactor; no production
code touched.

Why

• The test base mixes several call-count assertion shapes —
  LONGS_EQUAL(N, fooCallCount), LONGS_EQUAL(N, FakeFoo_BarCount()),
  CHECK_TRUE(barCalled) — with inconsistent naming
  (SenderFake_SendCount, StoreFake_WriteCount, g_sleepCallCount,
  storeFullCallbackCount).
• A single intent-named macro family makes test bodies read as English
  and centralises the naming contract via token paste, so future drift
  is caught at compile time rather than in review.
• Partial implementations already exist:
  • The bespoke CHECK_HANDLER_INVOKED_ONCE /
    CHECK_HANDLER_NOT_INVOKED macros in Tests/SolidSyslogErrorTest.cpp.
  • A more substantial expression-form CALLED_FUNCTION(f, n) in
    Tests/TestUtils.h plus a CososoTesting::NEVER/ONCE/... namespace,
    used today only in Tests/SolidSyslogSwitchingSenderTest.cpp.
  • This story generalises both into one consistent token-paste design
    so the naming rule is enforced at compile time.

In scope

Extend Tests/TestUtils.h (move into Tests/Support/TestUtils.h so
non-Tests/-root test executables — Tests/Example, Tests/FreeRtos —
can include it via the established Support include path), keeping the
existing CososoTesting namespace + NEVER/ONCE/TWICE/THRICE enum.
Replace the single existing CALLED_FUNCTION(f, n) macro with three
token-paste macros that enforce the <name>CallCount naming rule:

#define CALLED_FUNCTION(name, count)            LONGS_EQUAL((count), name##CallCount)
#define CALLED_FAKE(getter, count)              LONGS_EQUAL((count), getter##CallCount())
#define CALLED_FAKE_ON(getter, instance, count) LONGS_EQUAL((count), getter##CallCount(instance))

Migrate the pre-existing CALLED_FUNCTION(SenderFake_…(inner), N) call
sites in Tests/SolidSyslogSwitchingSenderTest.cpp to CALLED_FAKE_ON.

Rename non-conforming counters/getters to the <name>CallCount rule:

• SenderFake_SendCount → SenderFake_SendCallCount
• SenderFake_DisconnectCount → SenderFake_DisconnectCallCount
• StoreFake_WriteCount → StoreFake_WriteCallCount
• g_sleepCallCount → NoOpSleepCallCount (SolidSyslogTlsStreamTest.cpp)
• getPortCallCount / getHostCallCount → SpyGetPortCallCount /
  SpyGetHostCallCount (UDP and Stream sender tests)
• sleepCallCount → SleepFakeCallCount
  (Tests/Example/ExampleServiceThreadTest.cpp)
• storeFullCallbackCount → CountStoreFullInvocationsCallCount
• thresholdCallbackCount → CountThresholdCrossingsCallCount

Convert boolean call-flags to int counters so they route through
CALLED_FUNCTION:

• storeFullCallbackInvoked → StoreFullCallbackCallCount
• computeIntegrityCalled → SpyComputeIntegrityCallCount
• verifyIntegrityCalled → SpyVerifyIntegrityCallCount

Replace the bespoke macros in Tests/SolidSyslogErrorTest.cpp with the
generic form (CALLED_FUNCTION(handler, ONCE) /
CALLED_FUNCTION(handler, NEVER)).

Sweep every existing call-count assertion site (LONGS_EQUAL with a
CallCount operand; CHECK_TRUE/CHECK_FALSE on the converted bool flags)
to use the new macros across all test executables — main test exe,
ExampleTests, FreeRtos host tests, and the Winsock-build variants.

Out of scope

• Production code (Tier 1/2) — no production changes at all.
• lastCount in Tests/SolidSyslogBlockDeviceTest.cpp (byte count, not
  call count).
• spy.callCount struct member in
  Tests/Example/ExampleInteractiveTest.cpp (different shape, low
  payoff).
• Adding new tests or coverage — pure refactor of existing assertions.

Acceptance criteria

• Tests/Support/TestUtils.h defines the three macros and is reachable
  from every test executable that asserts on call counts.
• All *Count / call-flag variables and getters follow the
  <name>CallCount rule (only lastCount exception noted above
  remains).
• All call-count assertions use CALLED_FUNCTION, CALLED_FAKE, or
  CALLED_FAKE_ON — no LONGS_EQUAL / CHECK_TRUE against a counter
  or call-flag remains.
• Bespoke macros in SolidSyslogErrorTest.cpp removed.
• All CI checks pass; coverage unchanged within noise.

Notes

• Single PR, pure test refactor — large diff but mechanical.
• Pre-PR check list (per CLAUDE.md): build-linux-gcc, build-linux-clang,
  sanitize-linux-gcc, coverage-linux-gcc, analyze-tidy, analyze-cppcheck,
  analyze-format.

Parent epic: #254