From 6c4c2fc1c8ea7439cbd80a29d9cfaf92ebe468ff Mon Sep 17 00:00:00 2001
From: Brendan Zabarauskas <bjzaba@yahoo.com.au>
Date: Fri, 14 Dec 2012 16:05:18 +1000
Subject: [PATCH] Add more Quaternion unit tests.

---
 src/test/test_quat.rs | 39 +++++++++++++++++++++++++++++++++++----
 1 file changed, 35 insertions(+), 4 deletions(-)

diff --git a/src/test/test_quat.rs b/src/test/test_quat.rs
index 477203e..4d3a501 100644
--- a/src/test/test_quat.rs
+++ b/src/test/test_quat.rs
@@ -1,6 +1,7 @@
 use mat::*;
 use quat::*;
 use vec::*;
+use funs::exponential::sqrt;
 
 // TODO
 
@@ -11,8 +12,8 @@ fn test_Quat() {
     assert a == Quat::from_sv(1f, Vec3::new(2f, 3f, 4f));
     assert a == Quat::new(1f, 2f, 3f, 4f);
     
-    // assert Quat::zero()     == Quat::new(0f, 0f, 0f, 0f);
-    // assert Quat::identity() == Quat::new(1f, 0f, 0f, 0f);
+    assert Quat::zero()     == Quat::new(0f, 0f, 0f, 0f);
+    assert Quat::identity() == Quat::new(1f, 0f, 0f, 0f);
     
     assert a.s == 1f;
     assert a.v.x == 2f;
@@ -22,6 +23,36 @@ fn test_Quat() {
     assert a[1] == 2f;
     assert a[2] == 3f;
     assert a[3] == 4f;
-    
     // TODO
-}
\ No newline at end of file
+}
+
+#[test]
+fn test_quat_2() {
+    let v = Vec3::new(1.0, 0.0, 0.0);
+    
+    // let q: Quat<float> = Quaternion::from_axis_angle(&Vec3::new(0.0, 0.0, -1.0), Degrees(-90.0));
+    let q = Quat::from_axis_angle(&Vec3::new(0.0, 0.0, -1.0), Degrees(-45.0));
+    
+    // http://www.wolframalpha.com/input/?i={1,0}+rotate+-45+degrees
+    assert q.mul_v(&v).fuzzy_eq(&Vec3::new(1.0/sqrt(&2.0), 1.0/sqrt(&2.0), 0.0));
+    assert q.mul_v(&v).length() == v.length();
+    assert q.to_mat3().fuzzy_eq(&Mat3::new( 1.0/sqrt(&2.0), 1.0/sqrt(&2.0), 0.0,
+                                           -1.0/sqrt(&2.0), 1.0/sqrt(&2.0), 0.0,
+                                                       0.0,            0.0, 1.0));
+}
+
+/*
+
+Here is what I use to test my quaternions:
+
+* First, rotate an arbitrary vector around an arbitrary axis using an arbitrary angle (of course with a quaternion).
+
+* Then compare the original to the result vector, considering length and angle. If the length is constant and the angle is as desired, everything is fine and you are "green".
+
+* Now generate a series of rotation quaternions and concatenate them. Transform an arbitrary vector with it.
+
+* Now use each individual transformation of that series to transform the vector again, but this time checking angle and length like in the single transformation case. Only proceed while you stay "green".
+
+* Finally, compare both results. If they match, you are "green".
+
+*/
\ No newline at end of file