add test

tests/pragmas/twarning_off.nim

@@ -0,0 +1,17 @@
+discard """
+  nimout: '''
+compile start
+Hint: warn_module [Processing]
+Hint: hashes [Processing]
+warn_module.nim(4, 6) Hint: 'test' is declared but not used [XDeclaredButNotUsed]
+compile end
+'''
+"""
+
+static:
+  echo "compile start"
+
+import warn_module
+
+static:
+  echo "compile end"

tests/pragmas/warn_module.nim

@@ -0,0 +1,7 @@
+
+{.warning[UnusedImport]: off.}
+
+import hashes
+
+proc test(a: float): float =
+  a