Segmentation fault on publish BrakeCommand

DomasAquinas · Jun 5, 2022 · fc534c1 · fc534c1
1 parent c67bf2f
commit fc534c1
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Showing 5 changed files with 29 additions and 4 deletions.
diff --git a/chapter-10-testing/examples/AutoBrake.h b/chapter-10-testing/examples/AutoBrake.h
@@ -1,4 +1,5 @@
 // AutoBrake class template
+#pragma once
 
 #include <stdexcept>
 
@@ -7,14 +8,21 @@
 
 template <typename T>
 struct AutoBrake {
-    AutoBrake(const T& Publish)
-        : collision_threshold_s { 5 },
+    AutoBrake(const T& publish)
+        : collision_threshold_s{ 5 },
           speed_mps{},
           publish{ publish } { };
     void observe(const SpeedUpdate& su) {
         speed_mps = su.velocity_mps;
-    };
-    void observe(const CarDetected& cd) { };
+    }
+    void observe(const CarDetected& cd) {
+        const auto relative_velocity_mps = speed_mps - cd.velocity_mps;
+        const auto time_to_collision_s = cd.distance_m / relative_velocity_mps;
+        if (time_to_collision_s > 0 &&
+            time_to_collision_s <= collision_threshold_s) {
+                publish(BrakeCommand{ time_to_collision_s });
+        }
+    }
     void set_collision_threshold_s(double x) {
         if (x < 1) throw std::runtime_error{ "Collision less than 1." };
         collision_threshold_s = x;

diff --git a/chapter-10-testing/examples/AutoBrakePods.h b/chapter-10-testing/examples/AutoBrakePods.h
@@ -1,4 +1,5 @@
 // POD classes for the AutoBrake examples
+#pragma once
 
 struct SpeedUpdate {
     double velocity_mps;

diff --git a/chapter-10-testing/examples/ServiceBus.h b/chapter-10-testing/examples/ServiceBus.h
@@ -1,4 +1,5 @@
 // Service bus for the AutoBrake examples
+#pragma once
 
 struct BrakeCommand;
 

diff --git a/chapter-10-testing/examples/test_AutoBrake b/chapter-10-testing/examples/test_AutoBrake
diff --git a/chapter-10-testing/examples/test_AutoBrake.cpp b/chapter-10-testing/examples/test_AutoBrake.cpp
@@ -43,6 +43,20 @@ void speed_is_saved() {
     assert_that(0L == auto_brake.get_speed_mps(), "speed not saved to 0");
 }
 
+void alert_when_imminent() {
+    int brake_commands_published{};
+    AutoBrake auto_brake{
+        [&brake_commands_published](const BrakeCommand&) {
+            brake_commands_published++;
+        }
+    };
+    auto_brake.set_collision_threshold_s(10L);
+    auto_brake.observe(SpeedUpdate{ 100L });
+    auto_brake.observe(CarDetected{ 100L, 0L});
+    assert_that(brake_commands_published == 1,
+                "brake commands published not one");
+}
+
 // Test harness
 void run_test(void(*unit_test)(), const char* name) {
     try {
@@ -58,4 +72,5 @@ int main() {
     run_test(initial_sensitivity_is_five, "initial sensitivity is 5");
     run_test(sensitivity_greater_than_1, "sensitivity greater than 1");
     run_test(speed_is_saved, "speed is saved");
+    run_test(alert_when_imminent, "alert when imminent");
 }