interpreter: Add testcase..endtestcase clause support

This is currently only enabled when running unit tests to facilitate
writing failing unit tests.

Fixes: #11394

1 files changed, 13 insertions, 0 deletions

diff --git a/mesonbuild/interpreterbase/interpreterbase.py b/mesonbuild/interpreterbase/interpreterbase.py
index da64f68..c8ef303 100644
--- a/mesonbuild/interpreterbase/interpreterbase.py
+++ b/mesonbuild/interpreterbase/interpreterbase.py
@@ -26,6 +26,7 @@ from .baseobjects import (
     InterpreterObjectTypeVar,
     ObjectHolder,
     IterableObject,
+    ContextManagerObject,
 
     HoldableTypes,
 )
@@ -231,6 +232,8 @@ class InterpreterBase:
             raise ContinueRequest()
         elif isinstance(cur, mparser.BreakNode):
             raise BreakRequest()
+        elif isinstance(cur, mparser.TestCaseClauseNode):
+            return self.evaluate_testcase(cur)
         else:
             raise InvalidCode("Unknown statement.")
         return None
@@ -294,6 +297,16 @@ class InterpreterBase:
             self.evaluate_codeblock(node.elseblock)
         return None
 
+    def evaluate_testcase(self, node: mparser.TestCaseClauseNode) -> T.Optional[Disabler]:
+        result = self.evaluate_statement(node.condition)
+        if isinstance(result, Disabler):
+            return result
+        if not isinstance(result, ContextManagerObject):
+            raise InvalidCode(f'testcase clause {result!r} does not evaluate to a context manager.')
+        with result:
+            self.evaluate_codeblock(node.block)
+        return None
+
     def evaluate_comparison(self, node: mparser.ComparisonNode) -> InterpreterObject:
         val1 = self.evaluate_statement(node.left)
         if val1 is None: