Fix getKind for Python bindings (#4496)

I noticed recently that getKind for Op and Term was not correct in the python bindings. This PR would add maps to keep track of the Kind objects and the Python names (which are different from the C++ Kind names). Then a Python `kind` only needs the integer representation of a `Kind` to be constructed. Now, in `getKind` it can just pass the integer representation when constructing a `kind`.

.github/workflows/ci.yml

@@ -82,6 +82,12 @@ jobs:
         python3 -m pip install \
           Cython==0.29 --install-option="--no-cython-compile"
 
+    - name: Install Pytest
+      if: matrix.python-bindings
+      run: |
+        python3 -m pip install pytest
+        python3 -m pytest --version
+
     - name: Restore Dependencies
       id: restore-deps
       uses: actions/cache@v1
@@ -160,6 +166,12 @@ jobs:
        export PYTHONPATH="$PYTHONPATH:$(dirname $(find build/install/ -name "pycvc4" -type d))"
        python3 -c "import pycvc4"
 
+    - name: Run Pytest
+      if: matrix.python-bindings
+      run: |
+       export PYTHONPATH="$PYTHONPATH:$(dirname $(find build/install/ -name "pycvc4" -type d))"
+       python3 -m pytest ./test/unit/api/python
+
       # Examples are built for non-symfpu builds
     - name: Check Examples
       if: matrix.check-examples && runner.os == 'Linux'

src/api/python/cvc4.pxd

@@ -250,6 +250,7 @@ cdef extern from "api/cvc4cpp.h" namespace "CVC4::api":
         bint hasOp() except +
         Op getOp() except +
         bint isNull() except +
+        bint isConst() except +
         Term getConstArrayBase() except +
         Term notTerm() except +
         Term andTerm(const Term& t) except +

src/api/python/cvc4.pxi

@@ -1100,6 +1100,9 @@ cdef class Term:
     def isNull(self):
         return self.cterm.isNull()
 
+    def isConst(self):
+        return self.cterm.isConst()
+
     def getConstArrayBase(self):
         cdef Term term = Term()
         term.cterm = self.cterm.getConstArrayBase()

src/api/python/genkinds.py

@@ -69,11 +69,21 @@
 import sys
 from types import ModuleType
 
+from libcpp.string cimport string
+from libcpp.unordered_map cimport unordered_map
+
+# these maps are used for creating a kind
+# it is needed for dynamically making a kind
+# e.g. for getKind()
+cdef unordered_map[int, Kind] int2kind
+cdef unordered_map[int, string] int2name
+
 cdef class kind:
     cdef Kind k
     cdef str name
-    def __cinit__(self, str name):
-        self.name = name
+    def __cinit__(self, int kindint):
+        self.k = int2kind[kindint]
+        self.name = int2name[kindint].decode()
 
     def __eq__(self, kind other):
         return (<int> self.k) == (<int> other.k)
@@ -100,8 +110,9 @@ def as_int(self):
 
 KINDS_ATTR_TEMPLATE = \
 r"""
-cdef kind {name} = kind("{name}")
-{name}.k = {kind}
+int2kind[<int> {kind}] = {kind}
+int2name[<int> {kind}] = "{name}".encode()
+cdef kind {name} = kind(<int> {kind})
 setattr(kinds, "{name}", {name})
 """
 

test/unit/api/python/test_term.py

@@ -0,0 +1,88 @@
+import pytest
+
+import pycvc4
+from pycvc4 import kinds
+
+
+def test_get_kind():
+    solver = pycvc4.Solver()
+    intsort = solver.getIntegerSort()
+    x = solver.mkConst(intsort, 'x')
+    y = solver.mkConst(intsort, 'y')
+    xpy = solver.mkTerm(kinds.Plus, x, y)
+    assert xpy.getKind() == kinds.Plus
+
+    funsort = solver.mkFunctionSort(intsort, intsort)
+    f = solver.mkConst(funsort, 'f')
+    assert f.getKind() == kinds.Constant
+
+    fx = solver.mkTerm(kinds.ApplyUf, f, x)
+    assert fx.getKind() == kinds.ApplyUf
+
+
+def test_eq():
+    solver = pycvc4.Solver()
+    usort = solver.mkUninterpretedSort('u')
+    x = solver.mkConst(usort, 'x')
+    y = solver.mkConst(usort, 'y')
+    z = x
+
+    assert x == x
+    assert x == z
+    assert not (x != x)
+    assert x != y
+    assert y != z
+
+
+def test_get_sort():
+    solver = pycvc4.Solver()
+    intsort = solver.getIntegerSort()
+    bvsort8 = solver.mkBitVectorSort(8)
+
+    x = solver.mkConst(intsort, 'x')
+    y = solver.mkConst(intsort, 'y')
+
+    a = solver.mkConst(bvsort8, 'a')
+    b = solver.mkConst(bvsort8, 'b')
+
+    assert x.getSort() == intsort
+    assert solver.mkTerm(kinds.Plus, x, y).getSort() == intsort
+
+    assert a.getSort() == bvsort8
+    assert solver.mkTerm(kinds.BVConcat, a, b).getSort() == solver.mkBitVectorSort(16)
+
+def test_get_op():
+    solver = pycvc4.Solver()
+    intsort = solver.getIntegerSort()
+    funsort = solver.mkFunctionSort(intsort, intsort)
+
+    x = solver.mkConst(intsort, 'x')
+    f = solver.mkConst(funsort, 'f')
+
+    fx = solver.mkTerm(kinds.ApplyUf, f, x)
+
+    assert not x.hasOp()
+
+    try:
+        op = x.getOp()
+        assert False
+    except:
+        assert True
+
+    assert fx.hasOp()
+    assert fx.getOp().getKind() == kinds.ApplyUf
+    # equivalent check
+    assert fx.getOp() == solver.mkOp(kinds.ApplyUf)
+
+
+def test_is_const():
+    solver = pycvc4.Solver()
+    intsort = solver.getIntegerSort()
+    one = solver.mkReal(1)
+    x = solver.mkConst(intsort, 'x')
+    xpone = solver.mkTerm(kinds.Plus, x, one)
+    onepone = solver.mkTerm(kinds.Plus, one, one)
+    assert not x.isConst()
+    assert one.isConst()
+    assert not xpone.isConst()
+    assert not onepone.isConst()