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/src/MyTestPackage.jl

@@ -0,0 +1,6 @@
+module MyTestPackage
+
+include("find.jl")
+export find_max
+export find_mean
+end # module MyTestPackage

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

@@ -0,0 +1,16 @@
+
+function find_max(x::AbstractVector)
+    @assert all(!isnan,x)
+    currentmax = x[1]
+    for a = eachindex(x)
+        if x[a] > currentmax
+            currentmax = x[a]
+        end
+    end
+    return currentmax
+end
+
+function find_mean(x::AbstractVector)
+    @assert all(!isnan,x)
+    return sum(x)./length(x)
+end