From 5e379b1cf70006dbe782df991a655c475630a146 Mon Sep 17 00:00:00 2001
From: Sam Anthony <sam@samanthony.xyz>
Date: Sun, 2 Mar 2025 12:03:54 -0500
Subject: engine tests

---
 engine.c      |  2 +-
 test.c        |  5 +++-
 test.h        | 10 +++++++-
 test_engine.c | 82 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 4 files changed, 95 insertions(+), 4 deletions(-)

diff --git a/engine.c b/engine.c
index 00b3b48..ad1932e 100644
--- a/engine.c
+++ b/engine.c
@@ -98,5 +98,5 @@ density_ratio(const Engine *e) {
 	p3 = e->map;
 	t1 = e->ambient_temperature;
 	t3 = manifold_temperature(e);
-	return (p1 * t3) / (p3 * t1);
+	return (p3 * t1) / (p1 * t3);
 }
diff --git a/test.c b/test.c
index afaff5d..72952f5 100644
--- a/test.c
+++ b/test.c
@@ -49,7 +49,10 @@ main(void) {
 	test_as_cubic_foot_per_min();
 
 	test_comp_outlet_pressure();
-	test_comp_outlet_temperature();
 	test_pressure_ratio();
+	test_pressure_ratio_intercooled();
+	test_comp_outlet_temperature_adiabatic();
+	test_comp_outlet_temperature();
+	test_manifold_temperature();
 	test_volume_flow_rate();
 }
diff --git a/test.h b/test.h
index 4504b00..4f14ef8 100644
--- a/test.h
+++ b/test.h
@@ -2,7 +2,7 @@
 
 #define test(got, want) { \
 	if (got < want-EPSILON || got > want+EPSILON) { \
-		fprintf(stderr, "got %f; want %f\n", got, want); \
+		fprintf(stderr, "got %.7f; want %.7f\n", got, want); \
 		assert(got == want); \
 	} \
 }
@@ -53,3 +53,11 @@ void test_cubic_foot_per_min(void);
 void test_as_cubic_metre_per_sec(void);
 void test_as_cubic_metre_per_min(void);
 void test_as_cubic_foot_per_min(void);
+
+void test_comp_outlet_pressure(void);
+void test_pressure_ratio(void);
+void test_pressure_ratio_intercooled(void);
+void test_comp_outlet_temperature_adiabatic(void);
+void test_comp_outlet_temperature(void);
+void test_manifold_temperature(void);
+void test_volume_flow_rate(void);
diff --git a/test_engine.c b/test_engine.c
index 12f0c21..76e58fa 100644
--- a/test_engine.c
+++ b/test_engine.c
@@ -5,4 +5,84 @@
 #include "unit.h"
 #include "engine.h"
 
-/* TODO */
+void
+test_comp_outlet_pressure(void) {
+	Engine e;
+	init_engine(&e);
+	e.map = millibar(2000);
+	e.intercooler_deltap = psi(0.4);
+	test(comp_outlet_pressure(&e), millibar(2027.579029173));
+}
+
+void
+test_pressure_ratio(void) {
+	Engine e = {
+		.ambient_pressure = psi(14.3),
+		.map = psi(14.3+18),
+	};
+	test(pressure_ratio(&e), 2.2587413);
+
+}
+void
+test_pressure_ratio_intercooled(void) {
+	Engine e = {
+		.ambient_pressure = psi(14.3),
+		.map = psi(14.3+18),
+		.intercooler_deltap = psi(0.4),
+	};
+	test(pressure_ratio(&e), 2.2867133);
+}
+
+void
+test_comp_outlet_temperature_adiabatic(void) {
+	Engine e = {
+		.ambient_temperature = fahrenheit(70),
+		.ambient_pressure = psi(14.7),
+		.map = psi(31.7),
+		.comp_efficiency = percent(100),
+	};
+	test(comp_outlet_temperature(&e), kelvin(366.4715514));
+}
+
+void
+test_comp_outlet_temperature(void) {
+	Engine e = {
+		.ambient_temperature = fahrenheit(70),
+		.ambient_pressure = psi(14.7),
+		.map = psi(31.7),
+		.comp_efficiency = percent(70),
+	};
+	test(comp_outlet_temperature(&e), kelvin(397.418883));
+}
+
+void
+test_manifold_temperature(void) {
+	Engine e = {
+		.ambient_temperature = fahrenheit(80),
+		.ambient_pressure = millibar(1015.9166),
+		.map = millibar(2031.8332),
+		.comp_efficiency = percent(70),
+		.intercooler_efficiency = percent(70),
+	};
+	test(manifold_temperature(&e), kelvin(327.9429247));
+}
+
+
+void
+test_volume_flow_rate(void) {
+	Pressure p_ambient, p_boost, map;
+
+	p_ambient = millibar(982.052713333343);
+	p_boost = psi(10);
+	map = p_ambient + p_boost;
+	Engine e = {
+		.displacement = cubic_inch(250),
+		.rpm = rpm(5000),
+		.map = map,
+		.ambient_temperature = fahrenheit(70),
+		.ambient_pressure = p_ambient,
+		.ve = percent(80),
+		.comp_efficiency = percent(65),
+	};
+	test(volume_flow_rate(&e), cubic_metre_per_sec(0.1855992));
+}
-- 
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