add initial testing setup

tests/conftest.py

@@ -0,0 +1,65 @@
+from io import StringIO
+from typing import Any
+
+from xdsl.ir import Operation
+from xdsl.printer import Printer
+from xdsl.utils.diagnostic import Diagnostic
+
+
+def assert_print_op(
+    operation: Operation,
+    expected: str,
+    diagnostic: Diagnostic | None,
+    print_generic_format: bool = True,
+    print_debuginfo: bool = False,
+    **printer_options: Any,
+):
+    """
+    Utility function that helps to check the printing of an operation compared to
+    some string
+
+    Examples
+    --------
+    To check that an operation, namely Add prints as:
+
+    expected = \
+
+    builtin.module() {
+    %0 : !i32 = arith.addi(%<UNKNOWN> : !i32, %<UNKNOWN> : !i32)
+    -----------------------^^^^^^^^^^----------------------------------------------------------------
+    | ERROR: SSAValue is not part of the IR, are you sure all operations are added before their uses?
+    -------------------------------------------------------------------------------------------------
+    ------------------------------------------^^^^^^^^^^---------------------------------------------
+    | ERROR: SSAValue is not part of the IR, are you sure all operations are added before their uses?
+    -------------------------------------------------------------------------------------------------
+    %1 : !i32 = arith.addi(%0 : !i32, %0 : !i32)
+    }
+
+
+    we call:
+
+    .. code-block:: python
+
+        assert_print_op(add, expected)
+
+    Additional options can be passed to the printer using keyword arguments:
+
+    .. code-block:: python
+
+        assert_print_op(add, expected, print_unknown_value_error=False)
+
+    """
+
+    file = StringIO("")
+    if diagnostic is None:
+        diagnostic = Diagnostic()
+    printer = Printer(
+        stream=file,
+        print_generic_format=print_generic_format,
+        print_debuginfo=print_debuginfo,
+        diagnostic=diagnostic,
+        **printer_options,
+    )
+
+    printer.print(operation)
+    assert file.getvalue().strip() == expected.strip()