Add simple test for the dive planner

This sets up a standard dive scenario (30 minutes at 260ft/79m, EAN36 and
Oxygen as deco gases, last stop at 20ft/6m) and calls the planner to set
up a dive plan given certain standard gases.

Instead of trying to verify the complete plans it checks that we switch to
the deco gases at the right depth and the complete duration of the dive
matches our expectation.

The test intentionally fails right now for imperial as we have the wrong
switch depth for Oxygen. See how useful tests are?

On the downside, the test does NOT produce the same plan as Subsurface
when I try to create a consistent setup for both - and I have not been
able to figure out why. There must be some other parameters that I'm not
setting, but I haven't identified them, yet. It's very small differences,
for example in the metric case the stops at 21m, 9m, and 6m are each one
minute shorter in the test than it what Subsurface calculates.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

7 files changed, 148 insertions, 2 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 534e8e2b6..5f6d1fb24 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -520,6 +520,7 @@ if(NOT NO_TESTS)
 	TEST(TestProfile testprofile.cpp)
 	TEST(TestGpsCoords testgpscoords.cpp)
 	TEST(TestParse testparse.cpp)
+	TEST(TestPlan testplan.cpp)
 endif()
 
 # install a few things so that one can run Subsurface from the build
diff --git a/dive.c b/dive.c
index aadddfd14..8aac690a3 100644
--- a/dive.c
+++ b/dive.c
@@ -3119,3 +3119,17 @@ void delete_current_divecomputer(void)
 	if (dc_number == count_divecomputers())
 		dc_number--;
 }
+
+/* helper function to make it easier to work with our structures
+ * we don't interpolate here, just use the value from the last sample up to that time */
+int get_depth_at_time(struct divecomputer *dc, int time)
+{
+	int depth = 0;
+	if (dc && dc->sample)
+		for (int i = 0; i < dc->samples; i++) {
+			if (dc->sample[i].time.seconds > time)
+				break;
+			depth = dc->sample[i].depth.mm;
+		}
+	return depth;
+}
diff --git a/dive.h b/dive.h
index 042878c1b..9019511d1 100644
--- a/dive.h
+++ b/dive.h
@@ -393,6 +393,7 @@ extern timestamp_t picture_get_timestamp(char *filename);
 extern void dive_set_geodata_from_picture(struct dive *d, struct picture *pic);
 
 extern int explicit_first_cylinder(struct dive *dive, struct divecomputer *dc);
+extern int get_depth_at_time(struct divecomputer *dc, int time);
 
 static inline int get_surface_pressure_in_mbar(const struct dive *dive, bool non_null)
 {
diff --git a/planner.c b/planner.c
index 507cea03a..fcca0d78e 100644
--- a/planner.c
+++ b/planner.c
@@ -857,7 +857,6 @@ bool plan(struct diveplan *diveplan, char **cached_datap, bool is_planner, bool
 	int bottom_depth;
 	int bottom_gi;
 	int bottom_stopidx;
-
 	bool is_final_plan = true;
 	int deco_time;
 	int previous_deco_time;
diff --git a/planner.h b/planner.h
index 9a2c08b3d..ac146055d 100644
--- a/planner.h
+++ b/planner.h
@@ -11,7 +11,6 @@ extern "C" {
 extern int validate_gas(const char *text, struct gasmix *gas);
 extern int validate_po2(const char *text, int *mbar_po2);
 extern timestamp_t current_time_notz(void);
-extern void show_planned_dive(char **error_string_p);
 extern void set_last_stop(bool last_stop_6m);
 extern void set_verbatim(bool verbatim);
 extern void set_display_runtime(bool display);
diff --git a/tests/testplan.cpp b/tests/testplan.cpp
new file mode 100644
index 000000000..f08cfdeeb
--- /dev/null
+++ b/tests/testplan.cpp
@@ -0,0 +1,119 @@
+#include "dive.h"
+#include "testplan.h"
+#include "planner.h"
+#include "units.h"
+#include <QDebug>
+
+// testing the dive plan algorithm
+extern bool plan(struct diveplan *diveplan, char **cached_datap, bool is_planner, bool show_disclaimer);
+
+void setupPrefs()
+{
+	prefs = default_prefs;
+	prefs.ascrate50 = feet_to_mm(30) / 60;
+	prefs.ascrate75 = prefs.ascrate50;
+	prefs.ascratestops = prefs.ascrate50;
+	prefs.ascratelast6m = feet_to_mm(10) / 60;
+	prefs.last_stop = true;
+
+}
+
+void setupPlan(struct diveplan *dp)
+{
+	dp->salinity = 10030;
+	dp->surface_pressure = 1013;
+	dp->gfhigh = 100;
+	dp->gflow = 100;
+	dp->bottomsac = 0;
+	dp->decosac = 0;
+
+	struct gasmix bottomgas = { {150}, {450} };
+	struct gasmix ean36 = { {360}, {0} };
+	struct gasmix oxygen = { {1000}, {0} };
+	pressure_t po2 = { 1600 };
+	displayed_dive.cylinder[0].gasmix = bottomgas;
+	displayed_dive.cylinder[1].gasmix = ean36;
+	displayed_dive.cylinder[2].gasmix = oxygen;
+	reset_cylinders(&displayed_dive, true);
+	free_dps(dp);
+
+	int droptime = M_OR_FT(79, 260) * 60 / M_OR_FT(23, 75);
+	plan_add_segment(dp, droptime, M_OR_FT(79, 260), bottomgas, 0, 1);
+	plan_add_segment(dp, 30*60 - droptime, M_OR_FT(79, 260), bottomgas, 0, 1);
+	plan_add_segment(dp, 0, gas_mod(&ean36, po2, M_OR_FT(3,10)).mm, ean36, 0, 1);
+	plan_add_segment(dp, 0, gas_mod(&oxygen, po2, M_OR_FT(3,10)).mm, oxygen, 0, 1);
+}
+
+void TestPlan::testMetric()
+{
+	char *cache = NULL;
+
+	setupPrefs();
+	prefs.unit_system = METRIC;
+	prefs.units.length = units::METERS;
+	prefs.deco_mode = BUEHLMANN;
+
+	struct diveplan testPlan = { 0 };
+	setupPlan(&testPlan);
+
+	plan(&testPlan, &cache, 1, 0);
+
+#if DEBUG
+	free(displayed_dive.notes);
+	displayed_dive.notes = NULL;
+	save_dive(stdout, &displayed_dive);
+#endif
+
+	// check first gas change to EAN36 at 33m
+	struct event *ev = displayed_dive.dc.events;
+	QVERIFY(ev != NULL);
+	QCOMPARE(ev->gas.index, 1);
+	QCOMPARE(ev->value, 36);
+	QCOMPARE(get_depth_at_time(&displayed_dive.dc, ev->time.seconds), 33000);
+	// check second gas change to Oxygen at 6m
+	ev = ev->next;
+	QVERIFY(ev != NULL);
+	QCOMPARE(ev->gas.index, 2);
+	QCOMPARE(ev->value, 100);
+	QCOMPARE(get_depth_at_time(&displayed_dive.dc, ev->time.seconds), 6000);
+	// check expected run time of 105 minutes
+	QCOMPARE(displayed_dive.dc.duration.seconds, 104u * 60u);
+}
+
+void TestPlan::testImperial()
+{
+	char *cache = NULL;
+
+	setupPrefs();
+	prefs.unit_system = IMPERIAL;
+	prefs.units.length = units::FEET;
+	prefs.deco_mode = BUEHLMANN;
+
+	struct diveplan testPlan = { 0 };
+	setupPlan(&testPlan);
+
+	plan(&testPlan, &cache, 1, 0);
+
+#if DEBUG
+	free(displayed_dive.notes);
+	displayed_dive.notes = NULL;
+	save_dive(stdout, &displayed_dive);
+#endif
+
+	// check first gas change to EAN36 at 33m
+	struct event *ev = displayed_dive.dc.events;
+	QVERIFY(ev != NULL);
+	QCOMPARE(ev->gas.index, 1);
+	QCOMPARE(ev->value, 36);
+	QCOMPARE(get_depth_at_time(&displayed_dive.dc, ev->time.seconds), 33528);
+	// check second gas change to Oxygen at 6m
+	ev = ev->next;
+	QVERIFY(ev != NULL);
+	QCOMPARE(ev->gas.index, 2);
+	QCOMPARE(ev->value, 100);
+	QCOMPARE(get_depth_at_time(&displayed_dive.dc, ev->time.seconds), 6096);
+	// check expected run time of 105 minutes
+	QCOMPARE(displayed_dive.dc.duration.seconds, 105u * 60u);
+}
+
+QTEST_MAIN(TestPlan)
diff --git a/tests/testplan.h b/tests/testplan.h
new file mode 100644
index 000000000..b35cd75c6
--- /dev/null
+++ b/tests/testplan.h
@@ -0,0 +1,13 @@
+#ifndef TESTPLAN_H
+#define TESTPLAN_H
+
+#include <QTest>
+
+class TestPlan : public QObject {
+	Q_OBJECT
+private slots:
+	void testImperial();
+	void testMetric();
+};
+
+#endif // TESTPLAN_H