Add unit tests for UnaryOpExpression

This CL adds unit tests for the UnaryOpExpression AST element.

Bug: tint:11
Change-Id: I086d167c3b2ef0764a45a41268222254adba4017
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/16741
Reviewed-by: Sarah Mashayekhi <sarahmashay@google.com>
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index ac6c913..52c53c6 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -247,6 +247,7 @@
   ast/uint_literal_test.cc
   ast/unary_derivative_expression_test.cc
   ast/unary_method_expression_test.cc
+  ast/unary_op_expression_test.cc
   ast/variable_test.cc
   reader/wgsl/lexer_test.cc
   reader/wgsl/parser_test.cc