Supporting a button library.

libraries/button/src/button_mock.h

@@ -0,0 +1,60 @@
+#ifndef BUTTON_MOCK_H
+#define BUTTON_MOCK_H
+
+#include "button.h"
+
+/*
+ * Button -- Test mock with programmable state.
+ *
+ * Use this in tests to control exactly what button state your
+ * application sees, without any real hardware.
+ *
+ * Example:
+ *     ButtonMock btn;
+ *     btn.setPressed(true);
+ *
+ *     ToggleApp app(&sim, &btn);
+ *     app.update();
+ *
+ *     EXPECT_EQ(sim.getPin(LED_PIN), HIGH);  // LED should be on
+ *
+ * You can also track how many times the button was read:
+ *     btn.resetReadCount();
+ *     app.update();
+ *     EXPECT_EQ(btn.readCount(), 1);
+ */
+class ButtonMock : public Button {
+public:
+    /// Set whether the button appears pressed.
+    void setPressed(bool pressed) {
+        pressed_ = pressed;
+    }
+
+    /// Set the raw digital state returned by readState().
+    void setRaw(int value) {
+        raw_ = value;
+    }
+
+    bool isPressed() override {
+        ++read_count_;
+        return pressed_;
+    }
+
+    int readState() override {
+        ++read_count_;
+        return raw_;
+    }
+
+    /// How many times has the button been read?
+    int readCount() const { return read_count_; }
+
+    /// Reset the read counter.
+    void resetReadCount() { read_count_ = 0; }
+
+private:
+    bool pressed_ = false;  // Default: not pressed
+    int raw_ = HIGH;        // Default: HIGH (active-low, not pressed)
+    int read_count_ = 0;
+};
+
+#endif // BUTTON_MOCK_H