Python: Add concept tests

python/ql/test/experimental/library-tests/frameworks/stdlib/FileSystemAccess.py

@@ -0,0 +1,7 @@
+open("filepath")  # $getAPathArgument="filepath"
+open(file="filepath")  # $getAPathArgument="filepath"
+
+o = open
+
+o("filepath")  # f-:$getAPathArgument="filepath"
+o(file="filepath")  # f-:$getAPathArgument="filepath"

python/ql/test/experimental/library-tests/frameworks/stdlib/PathNormalization.py

@@ -0,0 +1,19 @@
+import os.path
+
+path = "un\\normalized/path"
+
+p1 = os.path.normpath(path)  # $pathNormalization
+p2 = os.path.normpath(path=path)  # $pathNormalization
+
+np = os.path.normpath
+
+p3 = np(path)  # $pathNormalization
+p4 = np(path=path)  # $pathNormalization
+
+
+def normalize(path):
+    return os.path.normpath(path)  # $pathNormalization
+
+
+p5 = normalize(path)
+p6 = normalize(path=path)

python/ql/test/experimental/library-tests/frameworks/stdlib/SafeAccessCheck.py

@@ -0,0 +1,4 @@
+s = "taintedString"
+
+if s.startswith("tainted"):  # $checks=s $branch=true
+    pass