--- a/src/options.rs	Tue Sep 19 20:09:41 2017 +0200
+++ b/src/options.rs	Tue Sep 19 20:11:59 2017 +0200
@@ -4,6 +4,7 @@
 use env::Env;
 use filter;
 use infolog::{self, Logger};
+use mem_env::MemEnv;
 use table_reader::TableBlock;
 use types::{share, SequenceNumber, Shared};
 
@@ -80,6 +81,7 @@
 
 pub fn for_test() -> Options {
     let mut o = Options::default();
+    o.env = Rc::new(Box::new(MemEnv::new()));
     o.log = share(infolog::stderr());
     o
 }

--- a/src/version.rs	Tue Sep 19 20:09:41 2017 +0200
+++ b/src/version.rs	Tue Sep 19 20:11:59 2017 +0200
@@ -535,7 +535,7 @@
 
     /// write_table creates a table with the given number and contents (must be sorted!) in the
     /// memenv. The sequence numbers given to keys start with startseq.
-    pub fn write_table(me: &MemEnv,
+    pub fn write_table(me: &Box<Env>,
                        contents: &[(&[u8], &[u8])],
                        startseq: u64,
                        num: FileNum)
@@ -565,8 +565,8 @@
     }
 
     pub fn make_version() -> (Version, Options) {
-        let mut opts = options::for_test();
-        let env = MemEnv::new();
+        let opts = options::for_test();
+        let env = opts.env.clone();
 
         // The different levels overlap in a sophisticated manner to be able to test compactions
         // and so on.
@@ -611,7 +611,6 @@
         let t9 = write_table(&env, f9, 25, 9);
 
 
-        opts.set_env(Box::new(env));
         let cache = TableCache::new("db", opts.clone(), 100);
         let mut v = Version::new(share(cache), Rc::new(Box::new(DefaultCmp)));
         v.files[0] = vec![t1, t2];