Add material for testing (#11)

* Add first draft material for testing

* added some first test stuff in julia

* add asserti error

* Rework intro slides

* added package

* Wrap up testing slides expect demo

* Smooth demo part

* Add statement on tests

* Remove previous python exercise file

---------

Co-authored-by: behinger (s-ccs 001) <benedikt.ehinger@vis.uni-stuttgart.de>

material/2_tue/testing/MyTestPackage/test/find.jl

@@ -0,0 +1,34 @@
+
+@testset "unit tests" begin
+    @testset "find_max" begin
+        @test find_max([1,2,3]) == 3
+        @test find_max([0,0,0]) == 0
+        
+        @test_throws AssertionError find_max([NaN,3,2])
+    end
+
+    @testset "find_mean" begin
+        @test find_mean([1,2,3]) == 2
+        @test find_mean([1,3,6]) ≈ 3.333 atol=1e-3
+      
+    end
+end
+
+@testset "integration test" begin
+    
+    data1 = [43, 32, 167, 18, 1, 209]
+    data2 = [3, 13, 33, 23, 498]
+
+    # Expected result
+    expected_mean_of_max = 353.5
+
+    maximum1 = find_max(data1)
+    maximum2 = find_max(data2)
+
+    # Actual result
+    actual_mean_of_max = find_mean([maximum1, maximum2])
+    
+    # Test
+    @test actual_mean_of_max == expected_mean_of_max
+    
+end