KnotTheory hacks and workarounds...

Workaround:
```
   BeginPackage["KnotTheory`", {"TubePlot`"}]
```

More generally, `BeginPackage[string, needs_list]` doesn't work.

Run `test/test_knottheory.py` only if KnotTheory environment variable is set.

mathics/builtin/scoping.py

@@ -650,6 +650,9 @@ class BeginPackage(Builtin):
              Protect[System`Private`$ContextPathStack, System`$Packages];
              context
         """,
+        # "BeginPackage[context_String, needs__]": """
+        #      BeginPackage[context]; Needs[Map[Needs, needs]];
+        # """
     }
 
 
@@ -680,6 +683,7 @@ class EndPackage(Builtin):
                                               System`Private`newctx],
                                       Most[System`Private`$ContextPathStack]};
                                  Protect[System`Private`$ContextPathStack];
+                                 Print["EndPackage: "<>System`Private`$ContextStack];
                                  Null]]
         """,
     }

mathics/packages/KnotTheory/init.m

@@ -767,7 +767,9 @@ crossing and False if it is positive (right handed).
 
 End[]; EndPackage[]
 
-BeginPackage["KnotTheory`", {"TubePlot`"}]
+(* BeginPackage["KnotTheory`", {"TubePlot`"}]*)
+Needs["TubePlot`"];
+BeginPackage["KnotTheory`"]
 
 TorusKnot;
 
@@ -781,7 +783,7 @@ crossing and False if it is positive (right handed).
   TubePlotPrelude -> EdgeForm[{}], Boxed -> False, ViewPoint -> {0, 0, 1}
 ];
 
-End[]; (*EndPackage[]*)
+End[]; EndPackage[]
 (* End source file src/TubePlot.m*)
 
 

test/test_knottheory.py

@@ -1,4 +1,7 @@
 # -*- coding: utf-8 -*-
+import os
+import pytest
+
 from .helper import evaluate, check_evaluation
 
 import pytest
@@ -10,6 +13,8 @@
 )
 
 
+@pytest.mark.skipif(not os.environ.get("KnotTheory", False),
+                    reason="set environment varable KnotTheory to run this test")
 def test_knottheory():
     evaluate(
         """K = PD[X[1,9,2,8], X[3,10,4,11],