Koans for basic arithmetic

lib/koans/07_arithmetic.ex

@@ -0,0 +1,62 @@
+defmodule Arithmetic do
+  use Koans
+
+  koan "it can add numbers" do
+    assert 3 + 4 == 7
+  end
+
+  koan "it can substract numbers" do
+    assert 7 - 4 == 3
+  end
+
+  koan "it can multiply" do
+    assert 3 * 4 == 12
+  end
+
+  koan "floats and integers can be equal..." do
+    assert 3.0 == 3
+  end
+
+  koan "..unless they are not precisely the same" do
+    assert 3.2 != 3
+  end
+
+  koan "it does floating point division" do
+    assert 5 / 2 == 2.5
+  end
+
+  koan "it does integer division" do
+    numerator = 5
+    denominator = 2
+    assert div(numerator, denominator) == 2
+  end
+
+  koan "it calculates the remainder of a division" do
+    numerator = 5
+    denominator = 2
+    assert rem(numerator, denominator) == 1
+  end
+
+  koan "it finds the maximum in a list" do
+    assert Enum.max([1,2,3,4]) == 4
+  end
+
+  koan "it can compare numbers" do
+    assert 5 > 2
+    assert 5 >= 5
+    assert 3 < 7
+    assert 5 <= 5
+  end
+
+  koan "it finds the minimum in a list" do
+    assert Enum.min([1,2,3,4]) == 1
+  end
+
+  koan "it can not divide by zero" do
+    try do
+      1 / 0.0
+    rescue
+       ArithmeticError -> true
+    end
+  end
+end

lib/runner.ex

@@ -5,7 +5,8 @@ defmodule Runner do
     Lists,
     Maps,
     Functions,
-    Enums
+    Enums,
+    Arithmetic
   ]
 
   def run do