test: add assertion-based unit tests (112 checks, no hardware deps)

.github/workflows/build.yml

@@ -27,6 +27,11 @@ jobs:
       - name: Build mock binary (Makefile.mac)
         run: make -f test/Makefile.mac
 
+      - name: Run unit tests (assertion-based)
+        run: |
+          make -f test/Makefile.unit
+          ./test_unit
+
       - name: Run celestial math tests
         run: |
           make -f test/Makefile.celestial

.gitignore

@@ -7,6 +7,7 @@ test_oled
 test_celestial
 test_neopixel
 test_ring
+test_unit
 weather_display_mac
 
 # Test output

test/Makefile.unit

@@ -0,0 +1,34 @@
+# Assertion-based unit tests for pure-logic subsystems.
+# No hardware drivers, no real HTTP calls.
+#
+# From the project root:
+#   make -f test/Makefile.unit        # build
+#   make -f test/Makefile.unit run    # build + run
+#   make -f test/Makefile.unit clean
+
+CXX      = g++
+CXXFLAGS = -std=c++17 -D_DEFAULT_SOURCE -Iinclude -Wall -Wextra -g
+
+# Only the pure-logic source files — no LCD, OLED, SPI, I2C, ring, or main.
+# test/stubs/weather_stub.cpp replaces src/weather.cpp so that
+# weather_cache.cpp can be compiled without a libcurl dependency.
+# An empty API key makes the stub return an invalid report immediately,
+# which is how we drive the cache failure state machine in tests.
+SRCS = \
+    src/weather_alerts.cpp       \
+    src/weather_cache.cpp        \
+    test/stubs/weather_stub.cpp  \
+    src/display_rotation.cpp     \
+    src/config.cpp
+
+TARGET = test_unit
+
+$(TARGET): test/test_unit.cpp $(SRCS)
+	$(CXX) $(CXXFLAGS) -o $(TARGET) test/test_unit.cpp $(SRCS)
+
+run: $(TARGET)
+	./$(TARGET)
+
+.PHONY: run clean
+clean:
+	rm -f $(TARGET)

test/stubs/weather_stub.cpp

@@ -0,0 +1,17 @@
+// Replaces src/weather.cpp in the unit test build.
+// No libcurl dependency — returns an invalid report for any call.
+// The empty-key path is what test_weather_cache.cpp uses to drive failures.
+#include "weather.h"
+#include "log.h"
+
+WeatherReport getWeatherReport(const std::string& apiKey,
+                                const std::string& city,
+                                std::string* /*rawResponse*/) {
+    WeatherReport report;
+    if (apiKey.empty()) {
+        LOG_ERROR("getWeatherReport: empty API key");
+        return report;
+    }
+    LOG_ERROR("getWeatherReport: no HTTP in unit-test build (key=" << city << ")");
+    return report;
+}