CQT-141-Qubit-declaration-added-to-simplest-circuit

opensquirrel/writer/writer.py

@@ -14,11 +14,14 @@ def __init__(self, register_manager: RegisterManager) -> None:
         self.register_manager = register_manager
         qubit_register_size = self.register_manager.get_qubit_register_size()
         qubit_register_name = self.register_manager.get_qubit_register_name()
+
         bit_register_size = self.register_manager.get_bit_register_size()
         bit_register_name = self.register_manager.get_bit_register_name()
-        self.output = "version 3.0\n\n{}\n{}\n".format(
-            f"qubit[{qubit_register_size}] {qubit_register_name}",
-            f"bit[{bit_register_size}] {bit_register_name}\n" if bit_register_size > 0 else "",
+        self.output = "version 3.0{}{}{}{}\n\n".format(
+            "\n\n" if qubit_register_size > 0 or bit_register_size > 0 else "",
+            (f"qubit[{qubit_register_size}] {qubit_register_name}" if qubit_register_size > 0 else ""),
+            "\n" if qubit_register_size > 0 and bit_register_size > 0 else "",
+            (f"bit[{bit_register_size}] {bit_register_name}" if bit_register_size > 0 else ""),
         )
 
     def visit_bit(self, bit: Bit) -> str:
@@ -84,7 +87,6 @@ def visit_comment(self, comment: Comment) -> None:
 
 def circuit_to_string(circuit: Circuit) -> str:
     writer_impl = _WriterImpl(circuit.register_manager)
-
     circuit.ir.accept(writer_impl)
 
     return writer_impl.output.rstrip() + "\n"  # remove all trailing lines and leave only one

test/writer/test_writer.py

@@ -129,3 +129,69 @@ def test_comment() -> None:
 CR(1.234) q[0], q[1]
 """
     )
+
+
+def test_string_representation() -> None:
+    """Tests the string representation of a circuit."""
+    # Only qubit
+    qc = Circuit.from_string(
+        """
+        version 3.0
+
+        qubit[1] q
+
+        """,
+    )
+    assert (
+        str(qc)
+        == """version 3.0
+
+qubit[1] q
+"""
+    )
+    # Qubit and bit
+    qc = Circuit.from_string(
+        """
+        version 3.0
+
+        qubit[1] q
+        bit[1] b
+
+        """,
+    )
+    assert (
+        str(qc)
+        == """version 3.0
+
+qubit[1] q
+bit[1] b
+"""
+    )
+    # Only bit
+    qc = Circuit.from_string(
+        """
+        version 3.0
+
+        bit[1] b
+
+        """,
+    )
+    assert (
+        str(qc)
+        == """version 3.0
+
+bit[1] b
+"""
+    )
+    # Empty declaration
+    qc = Circuit.from_string(
+        """
+        version 3.0
+
+        """,
+    )
+    assert (
+        str(qc)
+        == """version 3.0
+"""
+    )