update qubit array test (#68)

* update qubit array test

* handle size=0 independently

Author: jcjaskula-aws

oqpy/quantum_types.py

@@ -55,9 +55,11 @@ def to_ast(self, prog: Program) -> ast.Expression:
 
     def make_declaration_statement(self, program: Program) -> ast.Statement:
         """Make an ast statement that declares the OQpy variable."""
+        if self.size == 0:
+            raise ValueError("The size of the qubit register cannot be zero.")
         decl = ast.QubitDeclaration(
             ast.Identifier(self.name),
-            size=ast.IntegerLiteral(self.size) if self.size else self.size,
+            size=ast.IntegerLiteral(self.size) if self.size else None,
         )
         decl.annotations = make_annotations(self.annotations)
         return decl
@@ -85,10 +87,10 @@ def __init__(self, collection: Qubit, index: AstConvertible):
         self.collection = collection
         self.index = index
 
-    def to_ast(self, program: Program) -> ast.IndexExpression:
+    def to_ast(self, program: Program) -> ast.IndexedIdentifier:
         """Converts this indexed qubit array into an ast node."""
-        return ast.IndexExpression(
-            collection=to_ast(program, self.collection), index=[to_ast(program, self.index)]
+        return ast.IndexedIdentifier(
+            name=to_ast(program, self.collection), indices=[[to_ast(program, self.index)]]
         )
 
 

tests/test_directives.py

@@ -2282,21 +2282,34 @@ def test_include():
 def test_qubit_array():
     prog = oqpy.Program()
     q = oqpy.Qubit("q", size=2)
+    i = IntVar(2, "i")
     prog.gate(q[0], "h")
     prog.gate([q[0], q[1]], "cnot")
+    prog.gate([q[oqpy.Range(0, i)]], "cnot")
+
+    with pytest.raises(TypeError):
+        prog.gate([q[0:2]], "cnot")
+
+    s = oqpy.Qubit("s")
+    with pytest.raises(TypeError):
+        prog.gate(s[0], "h")
 
     expected = textwrap.dedent(
         """
         OPENQASM 3.0;
         qubit[2] q;
+        int[32] i = 2;
         h q[0];
         cnot q[0], q[1];
+        cnot q[0:i - 1];
         """
     ).strip()
 
     assert prog.to_qasm() == expected
+    _check_respects_type_hints(prog)
 
-    with pytest.raises(TypeError):
-        prog = oqpy.Program()
-        q = oqpy.Qubit("q")
-        prog.gate(q[0], "h")
+    prog_with_errors = oqpy.Program()
+    q0 = oqpy.Qubit("q0", size=0)
+    prog_with_errors.gate(q0, "h")
+    with pytest.raises(ValueError):
+        prog_with_errors.to_qasm()