Adds smaller code samples from Chapters 1-3 to the tester.

tests/niminaction/Chapter2/resultreject.nim

@@ -0,0 +1,33 @@
+discard """
+  line: 27
+  errormsg: "has to be discarded"
+"""
+
+# Page 35.
+
+proc implicit: string =
+  "I will be returned"
+  
+proc discarded: string =
+  discard "I will not be returned"
+
+proc explicit: string =
+  return "I will be returned"
+
+proc resultVar: string =
+  result = "I will be returned"
+  
+proc resultVar2: string =
+  result = ""
+  result.add("I will be ")
+  result.add("returned")
+
+proc resultVar3: string =
+  result = "I am the result"
+  "I will cause an error"
+
+doAssert implicit() == "I will be returned"
+doAssert discarded() == nil
+doAssert explicit() == "I will be returned"
+doAssert resultVar() == "I will be returned"
+doAssert resultVar2() == "I will be returned"