Add unit tests.

semantic-python/test/fixtures/2-06-nested-function-definition.py

@@ -0,0 +1,7 @@
+# CHECK-TREE: { const <- \a -> \b -> { identity <- \x -> x; identity a }; #record{ const: const }}
+
+def const(a, b):
+    def identity(x):
+        return x
+
+    return identity(a)

semantic-python/test/fixtures/2-07-closure-over-scope.py

@@ -0,0 +1,11 @@
+# CHECK-JQ: .scope.zilch[0].b[0].span  == { start: [8, 8], end: [ 8, 16 ] }
+# CHECK-JQ: .scope.result[0].a[0].span == { start: [5, 8], end: [ 5, 16 ] }
+
+def const(a, b):
+    def result():
+        return a
+
+    def zilch(b):
+        return b
+
+    return result()

semantic-python/test/fixtures/2-08-function-decorator.py

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+# CHECK-TREE: { passthru <- \x -> x; decorated <- \x -> x; decorated = passthru(decorated); #record { passthru: passthru, decorated: decorated }}
+def passthru(x):
+    return x
+
+@passthru
+def decorated(x):
+    return x