Python: Add jmespath tests

Author: RasmusWL

python/ql/test/library-tests/frameworks/jmespath/ConceptsTest.expected

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+import python
+import experimental.meta.ConceptsTest

python/ql/test/library-tests/frameworks/jmespath/ConceptsTest.ql

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+argumentToEnsureNotTaintedNotMarkedAsSpurious
+untaintedArgumentToEnsureTaintedNotMarkedAsMissing
+failures

python/ql/test/library-tests/frameworks/jmespath/InlineTaintTest.expected

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+import experimental.meta.InlineTaintTest

python/ql/test/library-tests/frameworks/jmespath/InlineTaintTest.ql

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+import jmespath
+
+def test_idna():
+    data = TAINTED_DICT
+
+    expression = jmespath.compile("foo.bar")
+
+    ensure_tainted(
+        jmespath.search("foo.bar", data), # $ MISSING: tainted
+        jmespath.search("foo.bar", data=data), # $ MISSING: tainted
+
+        expression.search(data), # $ MISSING: tainted
+        expression.search(value=data) # $ MISSING: tainted
+    )
+
+    # since ```jmespath.search("{wat: `foo`}", {})``` works (and outputs a dictionary),
+    # we _could_ add a taint-step from the search expression to the output. However, it
+    # seems more likely to lead to FPs than good results, so these have deliberately not
+    # been included.
+
+    ts = TAINTED_STRING
+    safe_data = {"foo": "bar"}
+
+    unsafe_expression = jmespath.compile(ts)
+
+    ensure_not_tainted(
+        jmespath.search(ts, safe_data),
+        jmespath.search(expression=ts, data=safe_data),
+
+        unsafe_expression,
+        unsafe_expression.search(safe_data),
+        unsafe_expression.search(value=safe_data),
+    )