diff --git a/src/assert.rs b/src/assert.rs
index 652883a..1a9da89 100644
--- a/src/assert.rs
+++ b/src/assert.rs
@@ -2,6 +2,7 @@
 //!
 //! [Output]: https://doc.rust-lang.org/std/process/struct.Output.html
 
+use std::borrow::Cow;
 use std::fmt;
 use std::process;
 use std::str;
@@ -723,47 +724,50 @@ where
 /// [`IntoOutputPredicate`]: trait.IntoOutputPredicate.html
 /// [Predicate]: https://docs.rs/predicates-core/1.0.0/predicates_core/trait.Predicate.html
 #[derive(Debug)]
-pub struct BytesContentOutputPredicate(predicates::ord::EqPredicate<&'static [u8]>);
+pub struct BytesContentOutputPredicate(Cow<'static, [u8]>);
 
 impl BytesContentOutputPredicate {
     pub(crate) fn new(value: &'static [u8]) -> Self {
-        let pred = predicates::ord::eq(value);
-        BytesContentOutputPredicate(pred)
-    }
-}
-
-impl predicates_core::reflection::PredicateReflection for BytesContentOutputPredicate {
-    fn parameters<'a>(
-        &'a self,
-    ) -> Box<dyn Iterator<Item = predicates_core::reflection::Parameter<'a>> + 'a> {
-        self.0.parameters()
+        BytesContentOutputPredicate(Cow::from(value))
     }
 
-    /// Nested `Predicate`s of the current `Predicate`.
-    fn children<'a>(
-        &'a self,
-    ) -> Box<dyn Iterator<Item = predicates_core::reflection::Child<'a>> + 'a> {
-        self.0.children()
+    pub(crate) fn from_vec(value: Vec<u8>) -> Self {
+        BytesContentOutputPredicate(Cow::from(value))
     }
 }
 
+impl predicates_core::reflection::PredicateReflection for BytesContentOutputPredicate {}
+
 impl predicates_core::Predicate<[u8]> for BytesContentOutputPredicate {
     fn eval(&self, item: &[u8]) -> bool {
-        self.0.eval(item)
+        self.0.as_ref() == item
     }
 
-    fn find_case<'a>(
-        &'a self,
+    fn find_case(
+        &self,
         expected: bool,
         variable: &[u8],
-    ) -> Option<predicates_core::reflection::Case<'a>> {
-        self.0.find_case(expected, variable)
+    ) -> Option<predicates_core::reflection::Case> {
+        let actual = self.eval(variable);
+        if expected == actual {
+            Some(predicates_core::reflection::Case::new(Some(self), actual))
+        } else {
+            None
+        }
     }
 }
 
 impl fmt::Display for BytesContentOutputPredicate {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        self.0.fmt(f)
+        predicates::ord::eq(self.0.as_ref()).fmt(f)
+    }
+}
+
+impl IntoOutputPredicate<BytesContentOutputPredicate> for Vec<u8> {
+    type Predicate = BytesContentOutputPredicate;
+
+    fn into_output(self) -> Self::Predicate {
+        Self::Predicate::from_vec(self)
     }
 }
 
@@ -1017,6 +1021,12 @@ mod test {
         assert!(pred.eval(b"Hello" as &[u8]));
     }
 
+    #[test]
+    fn into_output_from_vec() {
+        let pred = convert_output(vec![b'H', b'e', b'l', b'l', b'o']);
+        assert!(pred.eval(b"Hello" as &[u8]));
+    }
+
     #[test]
     fn into_output_from_str() {
         let pred = convert_output("Hello");
diff --git a/tests/assert.rs b/tests/assert.rs
index 126070f..c2727a4 100644
--- a/tests/assert.rs
+++ b/tests/assert.rs
@@ -102,6 +102,13 @@ fn stdout_example() {
         .assert()
         .stdout(b"hello\n" as &[u8]);
 
+    Command::cargo_bin("bin_fixture")
+        .unwrap()
+        .env("stdout", "hello")
+        .env("stderr", "world")
+        .assert()
+        .stdout(vec![b'h', b'e', b'l', b'l', b'o', b'\n']);
+
     Command::cargo_bin("bin_fixture")
         .unwrap()
         .env("stdout", "hello")
@@ -133,6 +140,13 @@ fn stderr_example() {
         .assert()
         .stderr(b"world\n" as &[u8]);
 
+    Command::cargo_bin("bin_fixture")
+        .unwrap()
+        .env("stdout", "hello")
+        .env("stderr", "world")
+        .assert()
+        .stderr(vec![b'w', b'o', b'r', b'l', b'd', b'\n']);
+
     Command::cargo_bin("bin_fixture")
         .unwrap()
         .env("stdout", "hello")