Fix doc tests

taiki-e · taiki-e · commit c14c0547ef0c · 2019-11-03T18:59:20.000+09:00
diff --git a/futures-task/Cargo.toml b/futures-task/Cargo.toml
@@ -26,3 +26,6 @@ unstable = []
 cfg-target-has-atomic = []
 
 [dependencies]
+
+[dev-dependencies]
+futures-preview = { path = "../futures", version = "=0.3.0-alpha.19" }
