diff --git a/test/test_all.scad b/test/test_all.scad
index 3fd4d3c7..695f5537 100644
--- a/test/test_all.scad
+++ b/test/test_all.scad
@@ -1,7 +1,6 @@
 // 2D
 include <test_rounded_square.scad>;
 include <test_line2d.scad>;
-include <test_hull_polyline2d.scad>;
 include <test_hexagons.scad>;
 
 // 3D
@@ -9,7 +8,6 @@ include <test_rounded_cube.scad>;
 include <test_rounded_cylinder.scad>;
 include <test_crystal_ball.scad>;
 include <test_line3d.scad>;
-include <test_hull_polyline3d.scad>;
 
 // Transformation
 include <test_bend.scad>;
@@ -22,6 +20,9 @@ include <test_rails2sections.scad>;
 include <test_in_polyline.scad>;
 include <test_trim_shape.scad>;
 include <test_midpt_smooth.scad>;
+include <test_angle_between.scad>;
+include <test_contours.scad>;
+include <test_in_shape.scad>;
 
 // Path
 include <test_bezier_curve.scad>;
diff --git a/test/test_angle_between.scad b/test/test_angle_between.scad
new file mode 100644
index 00000000..68887242
--- /dev/null
+++ b/test/test_angle_between.scad
@@ -0,0 +1,10 @@
+use <angle_between.scad>;
+
+module test_angle_between() {
+    echo("==== test_angle_between  ====");
+    assert(angle_between([0, 1], [1, 0]) == 90);
+    assert(angle_between([0, 1, 0], [1, 0, 0]) == 90);
+    assert(round(angle_between([1, 1, 0], [1, 1, sqrt(2)])) == 45);
+}
+
+test_angle_between();
\ No newline at end of file
diff --git a/test/test_contours.scad b/test/test_contours.scad
new file mode 100644
index 00000000..59e6c7cc
--- /dev/null
+++ b/test/test_contours.scad
@@ -0,0 +1,25 @@
+use <unittest.scad>;
+use <contours.scad>;
+
+module test_contours() {
+    echo("==== test_contours  ====");
+
+    min_value =  1;
+    max_value = 360;
+    resolution = 10;
+
+    function f(x, y) = sin(x) * cos(y) * 30;
+
+    points = [
+        for(y = [min_value:resolution:max_value])
+            [
+                for(x = [min_value:resolution:max_value]) 
+                    [x, y, f(x, y)]
+            ]
+    ];
+
+    assertEqualPoints([[21, 89.9963, 0], [31, 89.9963, 0]], contours(points, 0)[10]);
+    assertEqualPoints( [[11, 31], [11, 41], [1, 41], [1, 31]], contours(points, [0, 5])[10]);
+}
+
+test_contours();
\ No newline at end of file
diff --git a/test/test_hull_polyline2d.scad b/test/test_hull_polyline2d.scad
deleted file mode 100644
index 7da93543..00000000
--- a/test/test_hull_polyline2d.scad
+++ /dev/null
@@ -1,26 +0,0 @@
-use <unittest.scad>;
-include <hull_polyline2d.scad>;
-
-module test_hull_polyline2d_line_segment(index, point1, point2, radius) {
-    points = [[1, 2], [-5, -4], [-5, 3], [5, 5]];
-    line_width = 1;
-        
-    assertEqualPoint(points[index - 1], point1);
-    assertEqualPoint(points[index], point2);
-    assertEqualNum(line_width, radius * 2);    
-} 
-
-module test_hull_polyline2d() {
-    echo("==== test_hull_polyline2d ===="); 
-
-    $fn = 4;
-    points = [[1, 2], [-5, -4], [-5, 3], [5, 5]];
-    line_width = 1;
-
-    hull_polyline2d(
-        points = [[1, 2], [-5, -4], [-5, 3], [5, 5]], 
-        width = 1
-    );
-}
-
-test_hull_polyline2d();
\ No newline at end of file
diff --git a/test/test_hull_polyline3d.scad b/test/test_hull_polyline3d.scad
deleted file mode 100644
index 311df1d5..00000000
--- a/test/test_hull_polyline3d.scad
+++ /dev/null
@@ -1,38 +0,0 @@
-use <unittest.scad>;            
-include <hull_polyline3d.scad>;
-
-module test_hull_polyline3d_line_segment(index, point1, point2, radius) {
-    points = [
-        [1, 2, 3], 
-        [4, -5, -6], 
-        [-1, -3, -5], 
-        [0, 0, 0]
-    ];
-        
-    diameter = 1;
-
-    assertEqualPoint(points[index - 1], point1);
-    assertEqualPoint(points[index], point2);
-    assertEqualNum(diameter, radius * 2);    
-} 
-
-module test_hull_polyline3d() {
-    echo("==== test_hull_polyline3d ===="); 
-
-    points = [
-        [1, 2, 3], 
-        [4, -5, -6], 
-        [-1, -3, -5], 
-        [0, 0, 0]
-    ];
-        
-    diameter = 1;
-
-    hull_polyline3d(
-        points = points, 
-        diameter = diameter, 
-        $fn = 3
-    );
-}
-
-test_hull_polyline3d();
\ No newline at end of file
diff --git a/test/test_in_shape.scad b/test/test_in_shape.scad
new file mode 100644
index 00000000..51bdb25b
--- /dev/null
+++ b/test/test_in_shape.scad
@@ -0,0 +1,26 @@
+use <unittest.scad>;
+use <shape_taiwan.scad>;
+use <in_shape.scad>;
+
+module test_in_shape() {
+    echo("==== test_in_shape ====");
+    
+    points = shape_taiwan(30);
+
+    n = 200;
+    xs = rands(-9, 9, n, seed = 1);
+    ys = rands(-16, 16, n, seed = 1);
+
+    pts = [
+        for(i = [0:n - 1]) 
+            let(p = [xs[i], ys[i]]) 
+            if(in_shape(points, p, true))
+            p
+        ]; 
+
+    expected = [[-4.7504, -8.44515], [-1.86155, -3.30942], [-2.01761, -3.58686], [3.05543, 5.43187], [6.2336, 11.0819], [-3.36108, -5.97525], [0.441867, 0.785541], [-1.01785, -1.80951], [-4.86761, -8.65353], [0.61945, 1.10125], [-0.770313, -1.36945], [-1.24743, -2.21765], [5.01101, 8.90846], [3.88747, 6.91106], [5.44964, 9.68824], [0.326746, 0.580882], [6.57036, 11.6806], [5.92464, 10.5327], [5.93286, 10.5473], [-4.0851, -7.2624], [3.0695, 5.4569], [1.67518, 2.9781], [3.08977, 5.49293], [-1.58782, -2.82279], [-5.44408, -9.67837], [-3.78667, -6.73185], [5.09966, 9.06606], [-1.5743, -2.79876], [2.23254, 3.96896], [2.89144, 5.14034], [-3.62708, -6.44815], [-0.969579, -1.7237], [-5.00176, -8.89201], [-0.553707, -0.984367], [0.446389, 0.79358], [-3.61926, -6.43424], [1.519, 2.70045], [1.18642, 2.10918], [2.05089, 3.64603], [-4.30238, -7.64867], [-4.84172, -8.60751], [0.602073, 1.07035], [-0.124927, -0.222093], [0.730809, 1.29922], [4.77873, 8.49552], [5.26326, 9.35691], [6.89626, 12.26], [0.734187, 1.30522], [-0.936357, -1.66463], [7.05845, 12.5483], [-2.20348, -3.9173], [0.691645, 1.22959], [2.74138, 4.87356], [-2.4973, -4.43965], [1.27815, 2.27227], [2.48106, 4.41077], [3.42368, 6.08655], [2.65949, 4.72798], [-2.6291, -4.67395], [4.7382, 8.42346], [-2.58243, -4.59099], [4.55019, 8.08923], [6.86415, 12.2029], [-0.0340367, -0.0605098], [5.16513, 9.18245], [-2.60441, -4.63007], [-2.16354, -3.84629], [4.73256, 8.41344], [4.88871, 8.69104], [-3.57551, -6.35646], [4.9093, 8.72765], [1.41541, 2.51629], [3.76277, 6.68936], [-0.528466, -0.939494], [4.76267, 8.46696], [-0.586932, -1.04343], [-4.15798, -7.39197], [5.97047, 10.6142], [0.923849, 1.6424], [-0.495449, -0.880799], [4.36977, 7.76847], [-0.642393, -1.14203], [-4.85347, -8.62839], [0.148456, 0.263921], [-5.24577, -9.32581], [0.339514, 0.60358], [-1.86636, -3.31797], [0.176585, 0.313929], [-3.80308, -6.76103], [-4.82835, -8.58373], [-3.99026, -7.0938], [-4.79479, -8.52408], [1.2612, 2.24213], [-1.47732, -2.62635], [-2.37882, -4.22902], [5.63391, 10.0158], [-3.78432, -6.72768], [3.91305, 6.95653], [2.03307, 3.61434], [-1.31562, -2.33889], [4.53371, 8.05994], [-1.29937, -2.31], [-1.28912, -2.29176], [-2.48572, -4.41906], [5.07525, 9.02267], [2.09392, 3.72253], [2.77783, 4.93836], [-3.70153, -6.5805], [-2.50533, -4.45393], [-4.05639, -7.21136], [-2.31959, -4.12372], [4.3372, 7.71058], [-3.62376, -6.44223], [-5.32155, -9.46054], [7.07438, 12.5767], [4.66828, 8.29916], [2.72017, 4.83586], [5.64977, 10.044], [4.72632, 8.40234], [-0.804916, -1.43096], [0.572876, 1.01845], [0.158197, 0.28124], [-5.1183, -9.09919], [-0.681255, -1.21112], [4.75635, 8.45573], [-5.17079, -9.19252], [-2.58365, -4.59316], [1.37852, 2.45069], [6.11361, 10.8686], [2.21926, 3.94535], [-3.15868, -5.61544], [4.10421, 7.29637], [0.409259, 0.727572], [4.26261, 7.57797], [3.36705, 5.98587], [-1.3174, -2.34205], [4.11403, 7.31384], [4.61404, 8.20273], [-1.843, -3.27644]];
+	
+	assertEqualPoints(expected, pts);
+}
+
+test_in_shape();
\ No newline at end of file