diff --git a/src/lib.rs b/src/lib.rs
index f7a3907e..a7ac4d8e 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -25,7 +25,7 @@
 //!
 //! let mut engine = Engine::new();
 //! engine.register_fn("compute_something", compute_something);
-//! assert_eq!(engine.eval_file::<bool>("my_script.rhai"), Ok(true));
+//! assert_eq!(engine.eval_file::<bool>("my_script.rhai").unwrap(), true);
 //! ```
 //!
 //! [Check out the README on GitHub for more information!](https://github.com/jonathandturner/rhai)
diff --git a/tests/arrays.rs b/tests/arrays.rs
index 8b3d5884..cfd74e6e 100644
--- a/tests/arrays.rs
+++ b/tests/arrays.rs
@@ -1,19 +1,17 @@
-use rhai::Engine;
-use rhai::RegisterFn;
+use rhai::{Engine, EvalAltResult, RegisterFn};
 
 #[test]
-fn test_arrays() {
+fn test_arrays() -> Result<(), EvalAltResult> {
     let mut engine = Engine::new();
 
-    assert_eq!(engine.eval::<i64>("let x = [1, 2, 3]; x[1]"), Ok(2));
-    assert_eq!(
-        engine.eval::<i64>("let y = [1, 2, 3]; y[1] = 5; y[1]"),
-        Ok(5)
-    );
+    assert_eq!(engine.eval::<i64>("let x = [1, 2, 3]; x[1]")?, 2);
+    assert_eq!(engine.eval::<i64>("let y = [1, 2, 3]; y[1] = 5; y[1]")?, 5);
+
+    Ok(())
 }
 
 #[test]
-fn test_array_with_structs() {
+fn test_array_with_structs() -> Result<(), EvalAltResult> {
     #[derive(Clone)]
     struct TestStruct {
         x: i64,
@@ -45,7 +43,7 @@ fn test_array_with_structs() {
     engine.register_fn("update", TestStruct::update);
     engine.register_fn("new_ts", TestStruct::new);
 
-    assert_eq!(engine.eval::<i64>("let a = [new_ts()]; a[0].x"), Ok(1));
+    assert_eq!(engine.eval::<i64>("let a = [new_ts()]; a[0].x")?, 1);
 
     assert_eq!(
         engine.eval::<i64>(
@@ -53,7 +51,9 @@ fn test_array_with_structs() {
              a[0].x = 100;           \
              a[0].update();          \
              a[0].x",
-        ),
-        Ok(1100)
+        )?,
+        1100
     );
+
+    Ok(())
 }
diff --git a/tests/binary_ops.rs b/tests/binary_ops.rs
index a0f7c451..edf560aa 100644
--- a/tests/binary_ops.rs
+++ b/tests/binary_ops.rs
@@ -1,20 +1,22 @@
-use rhai::Engine;
+use rhai::{Engine, EvalAltResult};
 
 #[test]
-fn test_binary_ops() {
+fn test_binary_ops() -> Result<(), EvalAltResult> {
     let mut engine = Engine::new();
 
-    assert_eq!(engine.eval::<i64>("10 % 4"), Ok(2));
-    assert_eq!(engine.eval::<i64>("10 << 4"), Ok(160));
-    assert_eq!(engine.eval::<i64>("10 >> 4"), Ok(0));
-    assert_eq!(engine.eval::<i64>("10 & 4"), Ok(0));
-    assert_eq!(engine.eval::<i64>("10 | 4"), Ok(14));
-    assert_eq!(engine.eval::<i64>("10 ^ 4"), Ok(14));
+    assert_eq!(engine.eval::<i64>("10 % 4")?, 2);
+    assert_eq!(engine.eval::<i64>("10 << 4")?, 160);
+    assert_eq!(engine.eval::<i64>("10 >> 4")?, 0);
+    assert_eq!(engine.eval::<i64>("10 & 4")?, 0);
+    assert_eq!(engine.eval::<i64>("10 | 4")?, 14);
+    assert_eq!(engine.eval::<i64>("10 ^ 4")?, 14);
 
-    assert_eq!(engine.eval::<bool>("42 == 42"), Ok(true));
-    assert_eq!(engine.eval::<bool>("42 > 42"), Ok(false));
+    assert_eq!(engine.eval::<bool>("42 == 42")?, true);
+    assert_eq!(engine.eval::<bool>("42 > 42")?, false);
 
     // Incompatible types compare to false
-    assert_eq!(engine.eval::<bool>("true == 42"), Ok(false));
-    assert_eq!(engine.eval::<bool>(r#""42" == 42"#), Ok(false));
+    assert_eq!(engine.eval::<bool>("true == 42")?, false);
+    assert_eq!(engine.eval::<bool>(r#""42" == 42"#)?, false);
+
+    Ok(())
 }
diff --git a/tests/bit_shift.rs b/tests/bit_shift.rs
index 184f5262..7b0a4ab5 100644
--- a/tests/bit_shift.rs
+++ b/tests/bit_shift.rs
@@ -1,15 +1,15 @@
-use rhai::Engine;
+use rhai::{Engine, EvalAltResult};
 
 #[test]
-fn test_left_shift() {
+fn test_left_shift() -> Result<(), EvalAltResult> {
     let mut engine = Engine::new();
-
-    assert_eq!(engine.eval::<i64>("4 << 2"), Ok(16));
+    assert_eq!(engine.eval::<i64>("4 << 2")?, 16);
+    Ok(())
 }
 
 #[test]
-fn test_right_shift() {
+fn test_right_shift() -> Result<(), EvalAltResult> {
     let mut engine = Engine::new();
-
-    assert_eq!(engine.eval::<i64>("9 >> 1"), Ok(4));
+    assert_eq!(engine.eval::<i64>("9 >> 1")?, 4);
+    Ok(())
 }
diff --git a/tests/bool_op.rs b/tests/bool_op.rs
index ffd90746..7c1654bb 100644
--- a/tests/bool_op.rs
+++ b/tests/bool_op.rs
@@ -1,42 +1,39 @@
 use rhai::{Engine, EvalAltResult};
 
 #[test]
-fn test_bool_op1() {
+fn test_bool_op1() -> Result<(), EvalAltResult> {
     let mut engine = Engine::new();
 
-    assert_eq!(engine.eval::<bool>("true && (false || true)"), Ok(true));
-    assert_eq!(engine.eval::<bool>("true & (false | true)"), Ok(true));
+    assert_eq!(engine.eval::<bool>("true && (false || true)")?, true);
+    assert_eq!(engine.eval::<bool>("true & (false | true)")?, true);
+
+    Ok(())
 }
 
 #[test]
-fn test_bool_op2() {
+fn test_bool_op2() -> Result<(), EvalAltResult> {
     let mut engine = Engine::new();
 
-    assert_eq!(engine.eval::<bool>("false && (false || true)"), Ok(false));
-    assert_eq!(engine.eval::<bool>("false & (false | true)"), Ok(false));
+    assert_eq!(engine.eval::<bool>("false && (false || true)")?, false);
+    assert_eq!(engine.eval::<bool>("false & (false | true)")?, false);
+
+    Ok(())
 }
 
 #[test]
-fn test_bool_op3() {
+fn test_bool_op3() -> Result<(), EvalAltResult> {
     let mut engine = Engine::new();
 
-    assert_eq!(
-        engine.eval::<bool>("true && (false || 123)"),
-        Err(EvalAltResult::ErrorBooleanArgMismatch("OR".into()))
-    );
+    assert!(engine.eval::<bool>("true && (false || 123)").is_err());
+    assert_eq!(engine.eval::<bool>("true && (true || 123)")?, true);
+    assert!(engine.eval::<bool>("123 && (false || true)").is_err());
+    assert_eq!(engine.eval::<bool>("false && (true || 123)")?, false);
 
-    assert_eq!(engine.eval::<bool>("true && (true || 123)"), Ok(true));
-
-    assert_eq!(
-        engine.eval::<bool>("123 && (false || true)"),
-        Err(EvalAltResult::ErrorBooleanArgMismatch("AND".into()))
-    );
-
-    assert_eq!(engine.eval::<bool>("false && (true || 123)"), Ok(false));
+    Ok(())
 }
 
 #[test]
-fn test_bool_op_short_circuit() {
+fn test_bool_op_short_circuit() -> Result<(), EvalAltResult> {
     let mut engine = Engine::new();
 
     assert_eq!(
@@ -47,8 +44,8 @@ fn test_bool_op_short_circuit() {
 
             this() || that();
         "
-        ),
-        Ok(true)
+        )?,
+        true
     );
 
     assert_eq!(
@@ -59,9 +56,11 @@ fn test_bool_op_short_circuit() {
 
             this() && that();
         "
-        ),
-        Ok(false)
+        )?,
+        false
     );
+
+    Ok(())
 }
 
 #[test]
@@ -70,15 +69,17 @@ fn test_bool_op_no_short_circuit1() {
     let mut engine = Engine::new();
 
     assert_eq!(
-        engine.eval::<bool>(
-            r"
-            fn this() { false }
-            fn that() { 9/0 }
+        engine
+            .eval::<bool>(
+                r"
+                    fn this() { false }
+                    fn that() { 9/0 }
 
-            this() | that();
-        "
-        ),
-        Ok(false)
+                    this() | that();
+                "
+            )
+            .unwrap(),
+        false
     );
 }
 
@@ -88,14 +89,16 @@ fn test_bool_op_no_short_circuit2() {
     let mut engine = Engine::new();
 
     assert_eq!(
-        engine.eval::<bool>(
-            r"
-            fn this() { false }
-            fn that() { 9/0 }
+        engine
+            .eval::<bool>(
+                r"
+                    fn this() { false }
+                    fn that() { 9/0 }
 
-            this() & that();
-        "
-        ),
-        Ok(false)
+                    this() & that();
+                "
+            )
+            .unwrap(),
+        false
     );
 }
diff --git a/tests/chars.rs b/tests/chars.rs
index 44657000..4a5c2d98 100644
--- a/tests/chars.rs
+++ b/tests/chars.rs
@@ -1,24 +1,19 @@
-use rhai::Engine;
+use rhai::{Engine, EvalAltResult};
 
 #[test]
-fn test_chars() {
+fn test_chars() -> Result<(), EvalAltResult> {
     let mut engine = Engine::new();
 
-    assert_eq!(engine.eval::<char>("'y'"), Ok('y'));
-    assert_eq!(engine.eval::<char>("'\\u2764'"), Ok('❤'));
-    assert_eq!(engine.eval::<char>(r#"let x="hello"; x[2]"#), Ok('l'));
+    assert_eq!(engine.eval::<char>("'y'")?, 'y');
+    assert_eq!(engine.eval::<char>("'\\u2764'")?, '❤');
+    assert_eq!(engine.eval::<char>(r#"let x="hello"; x[2]"#)?, 'l');
     assert_eq!(
-        engine.eval::<String>(r#"let x="hello"; x[2]='$'; x"#),
-        Ok("he$lo".into())
+        engine.eval::<String>(r#"let x="hello"; x[2]='$'; x"#)?,
+        "he$lo".to_string()
     );
 
-    match engine.eval::<char>("'\\uhello'") {
-        Err(_) => (),
-        _ => assert!(false),
-    }
+    assert!(engine.eval::<char>("'\\uhello'").is_err());
+    assert!(engine.eval::<char>("''").is_err());
 
-    match engine.eval::<char>("''") {
-        Err(_) => (),
-        _ => assert!(false),
-    }
+    Ok(())
 }
diff --git a/tests/compound_equality.rs b/tests/compound_equality.rs
index 7b51692a..65b3b3e4 100644
--- a/tests/compound_equality.rs
+++ b/tests/compound_equality.rs
@@ -1,68 +1,66 @@
-use rhai::Engine;
+use rhai::{Engine, EvalAltResult};
 
 #[test]
-fn test_or_equals() {
+fn test_or_equals() -> Result<(), EvalAltResult> {
     let mut engine = Engine::new();
 
-    assert_eq!(engine.eval::<i64>("let x = 16; x |= 74; x"), Ok(90));
-    assert_eq!(engine.eval::<bool>("let x = true; x |= false; x"), Ok(true));
-    assert_eq!(engine.eval::<bool>("let x = false; x |= true; x"), Ok(true));
+    assert_eq!(engine.eval::<i64>("let x = 16; x |= 74; x")?, 90);
+    assert_eq!(engine.eval::<bool>("let x = true; x |= false; x")?, true);
+    assert_eq!(engine.eval::<bool>("let x = false; x |= true; x")?, true);
+
+    Ok(())
 }
 
 #[test]
-fn test_and_equals() {
+fn test_and_equals() -> Result<(), EvalAltResult> {
     let mut engine = Engine::new();
 
-    assert_eq!(engine.eval::<i64>("let x = 16; x &= 31; x"), Ok(16));
-    assert_eq!(
-        engine.eval::<bool>("let x = true; x &= false; x"),
-        Ok(false)
-    );
-    assert_eq!(
-        engine.eval::<bool>("let x = false; x &= true; x"),
-        Ok(false)
-    );
-    assert_eq!(engine.eval::<bool>("let x = true; x &= true; x"), Ok(true));
+    assert_eq!(engine.eval::<i64>("let x = 16; x &= 31; x")?, 16);
+    assert_eq!(engine.eval::<bool>("let x = true; x &= false; x")?, false);
+    assert_eq!(engine.eval::<bool>("let x = false; x &= true; x")?, false);
+    assert_eq!(engine.eval::<bool>("let x = true; x &= true; x")?, true);
+
+    Ok(())
 }
 
 #[test]
-fn test_xor_equals() {
+fn test_xor_equals() -> Result<(), EvalAltResult> {
     let mut engine = Engine::new();
-
-    assert_eq!(engine.eval::<i64>("let x = 90; x ^= 12; x"), Ok(86));
+    assert_eq!(engine.eval::<i64>("let x = 90; x ^= 12; x")?, 86);
+    Ok(())
 }
 
 #[test]
-fn test_multiply_equals() {
+fn test_multiply_equals() -> Result<(), EvalAltResult> {
     let mut engine = Engine::new();
-
-    assert_eq!(engine.eval::<i64>("let x = 2; x *= 3; x"), Ok(6));
+    assert_eq!(engine.eval::<i64>("let x = 2; x *= 3; x")?, 6);
+    Ok(())
 }
 
 #[test]
-fn test_divide_equals() {
+fn test_divide_equals() -> Result<(), EvalAltResult> {
     let mut engine = Engine::new();
-
-    assert_eq!(engine.eval::<i64>("let x = 6; x /= 2; x"), Ok(3));
+    assert_eq!(engine.eval::<i64>("let x = 6; x /= 2; x")?, 3);
+    Ok(())
 }
 
 #[test]
-fn test_left_shift_equals() {
+fn test_left_shift_equals() -> Result<(), EvalAltResult> {
     let mut engine = Engine::new();
-
-    assert_eq!(engine.eval::<i64>("let x = 9; x >>=1; x"), Ok(4));
+    assert_eq!(engine.eval::<i64>("let x = 9; x >>=1; x")?, 4);
+    Ok(())
 }
 
 #[test]
-fn test_right_shift_equals() {
+fn test_right_shift_equals() -> Result<(), EvalAltResult> {
     let mut engine = Engine::new();
-
-    assert_eq!(engine.eval::<i64>("let x = 4; x<<= 2; x"), Ok(16));
+    assert_eq!(engine.eval::<i64>("let x = 4; x<<= 2; x")?, 16);
+    Ok(())
 }
 
 #[test]
-fn test_modulo_equals() {
+fn test_modulo_equals() -> Result<(), EvalAltResult> {
     let mut engine = Engine::new();
-
-    assert_eq!(engine.eval::<i64>("let x = 10; x %= 4; x"), Ok(2));
+    assert_eq!(engine.eval::<i64>("let x = 10; x %= 4; x")?, 2);
+    Ok(())
 }
diff --git a/tests/decrement.rs b/tests/decrement.rs
index ab1dc6c8..344c70ac 100644
--- a/tests/decrement.rs
+++ b/tests/decrement.rs
@@ -1,16 +1,17 @@
-use rhai::Engine;
-use rhai::EvalAltResult;
+use rhai::{Engine, EvalAltResult};
 
 #[test]
-fn test_decrement() {
+fn test_decrement() -> Result<(), EvalAltResult> {
     let mut engine = Engine::new();
 
-    assert_eq!(engine.eval::<i64>("let x = 10; x -= 7; x"), Ok(3));
+    assert_eq!(engine.eval::<i64>("let x = 10; x -= 7; x")?, 3);
 
-    assert_eq!(
-        engine.eval::<String>("let s = \"test\"; s -= \"ing\"; s"),
-        Err(EvalAltResult::ErrorFunctionNotFound(
-            "- (alloc::string::String, alloc::string::String)".to_string()
-        ))
-    );
+    let r = engine.eval::<String>("let s = \"test\"; s -= \"ing\"; s");
+
+    match r {
+        Err(EvalAltResult::ErrorFunctionNotFound(err, _)) if err.starts_with("- ") => (),
+        _ => panic!(),
+    }
+
+    Ok(())
 }
diff --git a/tests/float.rs b/tests/float.rs
index 516980d8..8e291e9e 100644
--- a/tests/float.rs
+++ b/tests/float.rs
@@ -1,23 +1,24 @@
-use rhai::Engine;
-use rhai::RegisterFn;
+use rhai::{Engine, EvalAltResult, RegisterFn};
 
 #[test]
-fn test_float() {
+fn test_float() -> Result<(), EvalAltResult> {
     let mut engine = Engine::new();
 
     assert_eq!(
-        engine.eval::<bool>("let x = 0.0; let y = 1.0; x < y"),
-        Ok(true)
+        engine.eval::<bool>("let x = 0.0; let y = 1.0; x < y")?,
+        true
     );
     assert_eq!(
-        engine.eval::<bool>("let x = 0.0; let y = 1.0; x > y"),
-        Ok(false)
+        engine.eval::<bool>("let x = 0.0; let y = 1.0; x > y")?,
+        false
     );
-    assert_eq!(engine.eval::<f64>("let x = 9.9999; x"), Ok(9.9999));
+    assert_eq!(engine.eval::<f64>("let x = 9.9999; x")?, 9.9999);
+
+    Ok(())
 }
 
 #[test]
-fn struct_with_float() {
+fn struct_with_float() -> Result<(), EvalAltResult> {
     #[derive(Clone)]
     struct TestStruct {
         x: f64,
@@ -50,11 +51,13 @@ fn struct_with_float() {
     engine.register_fn("new_ts", TestStruct::new);
 
     assert_eq!(
-        engine.eval::<f64>("let ts = new_ts(); ts.update(); ts.x"),
-        Ok(6.789)
+        engine.eval::<f64>("let ts = new_ts(); ts.update(); ts.x")?,
+        6.789
     );
     assert_eq!(
-        engine.eval::<f64>("let ts = new_ts(); ts.x = 10.1001; ts.x"),
-        Ok(10.1001)
+        engine.eval::<f64>("let ts = new_ts(); ts.x = 10.1001; ts.x")?,
+        10.1001
     );
+
+    Ok(())
 }
diff --git a/tests/for.rs b/tests/for.rs
index 687c1b4b..63390b31 100644
--- a/tests/for.rs
+++ b/tests/for.rs
@@ -1,7 +1,7 @@
-use rhai::Engine;
+use rhai::{Engine, EvalAltResult};
 
 #[test]
-fn test_for() {
+fn test_for() -> Result<(), EvalAltResult> {
     let mut engine = Engine::new();
 
     let script = r"
@@ -20,5 +20,7 @@ fn test_for() {
         sum1 + sum2
     ";
 
-    assert_eq!(engine.eval::<i64>(script).unwrap(), 30);
+    assert_eq!(engine.eval::<i64>(script)?, 30);
+
+    Ok(())
 }
diff --git a/tests/get_set.rs b/tests/get_set.rs
index e3311278..d2718a50 100644
--- a/tests/get_set.rs
+++ b/tests/get_set.rs
@@ -1,8 +1,7 @@
-use rhai::Engine;
-use rhai::RegisterFn;
+use rhai::{Engine, EvalAltResult, RegisterFn};
 
 #[test]
-fn test_get_set() {
+fn test_get_set() -> Result<(), EvalAltResult> {
     #[derive(Clone)]
     struct TestStruct {
         x: i64,
@@ -29,14 +28,13 @@ fn test_get_set() {
     engine.register_get_set("x", TestStruct::get_x, TestStruct::set_x);
     engine.register_fn("new_ts", TestStruct::new);
 
-    assert_eq!(
-        engine.eval::<i64>("let a = new_ts(); a.x = 500; a.x"),
-        Ok(500)
-    );
+    assert_eq!(engine.eval::<i64>("let a = new_ts(); a.x = 500; a.x")?, 500);
+
+    Ok(())
 }
 
 #[test]
-fn test_big_get_set() {
+fn test_big_get_set() -> Result<(), EvalAltResult> {
     #[derive(Clone)]
     struct TestChild {
         x: i64,
@@ -88,7 +86,9 @@ fn test_big_get_set() {
     engine.register_fn("new_tp", TestParent::new);
 
     assert_eq!(
-        engine.eval::<i64>("let a = new_tp(); a.child.x = 500; a.child.x"),
-        Ok(500)
+        engine.eval::<i64>("let a = new_tp(); a.child.x = 500; a.child.x")?,
+        500
     );
+
+    Ok(())
 }
diff --git a/tests/if_block.rs b/tests/if_block.rs
index 7440e448..286aa7fd 100644
--- a/tests/if_block.rs
+++ b/tests/if_block.rs
@@ -1,15 +1,15 @@
-use rhai::Engine;
+use rhai::{Engine, EvalAltResult};
 
 #[test]
-fn test_if() {
+fn test_if() -> Result<(), EvalAltResult> {
     let mut engine = Engine::new();
 
-    assert_eq!(engine.eval::<i64>("if true { 55 }"), Ok(55));
-    assert_eq!(engine.eval::<i64>("if false { 55 } else { 44 }"), Ok(44));
-    assert_eq!(engine.eval::<i64>("if true { 55 } else { 44 }"), Ok(55));
+    assert_eq!(engine.eval::<i64>("if true { 55 }")?, 55);
+    assert_eq!(engine.eval::<i64>("if false { 55 } else { 44 }")?, 44);
+    assert_eq!(engine.eval::<i64>("if true { 55 } else { 44 }")?, 55);
     assert_eq!(
-        engine.eval::<i64>("if false { 55 } else if true { 33 } else { 44 }"),
-        Ok(33)
+        engine.eval::<i64>("if false { 55 } else if true { 33 } else { 44 }")?,
+        33
     );
     assert_eq!(
         engine.eval::<i64>(
@@ -21,7 +21,9 @@ fn test_if() {
                 else if false { 88 }
                 else { 44 }
         "
-        ),
-        Ok(44)
+        )?,
+        44
     );
+
+    Ok(())
 }
diff --git a/tests/increment.rs b/tests/increment.rs
index 661ae38e..62b1b36c 100644
--- a/tests/increment.rs
+++ b/tests/increment.rs
@@ -1,12 +1,14 @@
-use rhai::Engine;
+use rhai::{Engine, EvalAltResult};
 
 #[test]
-fn test_increment() {
+fn test_increment() -> Result<(), EvalAltResult> {
     let mut engine = Engine::new();
 
-    assert_eq!(engine.eval::<i64>("let x = 1; x += 2; x"), Ok(3));
+    assert_eq!(engine.eval::<i64>("let x = 1; x += 2; x")?, 3);
     assert_eq!(
-        engine.eval::<String>("let s = \"test\"; s += \"ing\"; s"),
-        Ok("testing".to_string())
+        engine.eval::<String>("let s = \"test\"; s += \"ing\"; s")?,
+        "testing".to_string()
     );
+
+    Ok(())
 }
diff --git a/tests/internal_fn.rs b/tests/internal_fn.rs
index f04a46ca..95f584a5 100644
--- a/tests/internal_fn.rs
+++ b/tests/internal_fn.rs
@@ -1,25 +1,30 @@
-use rhai::Engine;
+use rhai::{Engine, EvalAltResult};
 
 #[test]
-fn test_internal_fn() {
+fn test_internal_fn() -> Result<(), EvalAltResult> {
     let mut engine = Engine::new();
 
-    assert_eq!(
-        engine.eval::<i64>("fn addme(a, b) { a+b } addme(3, 4)"),
-        Ok(7)
-    );
-    assert_eq!(engine.eval::<i64>("fn bob() { return 4; 5 } bob()"), Ok(4));
+    assert_eq!(engine.eval::<i64>("fn addme(a, b) { a+b } addme(3, 4)")?, 7);
+    assert_eq!(engine.eval::<i64>("fn bob() { return 4; 5 } bob()")?, 4);
+
+    Ok(())
 }
 
 #[test]
-fn test_big_internal_fn() {
+fn test_big_internal_fn() -> Result<(), EvalAltResult> {
     let mut engine = Engine::new();
 
     assert_eq!(
         engine.eval::<i64>(
-            "fn mathme(a, b, c, d, e, f) { a - b * c + d * e - f \
-             } mathme(100, 5, 2, 9, 6, 32)",
-        ),
-        Ok(112)
+            r"
+                fn mathme(a, b, c, d, e, f) {
+                    a - b * c + d * e - f
+                }
+                mathme(100, 5, 2, 9, 6, 32)
+            ",
+        )?,
+        112
     );
+
+    Ok(())
 }
diff --git a/tests/looping.rs b/tests/looping.rs
index 4359df16..4baa0aab 100644
--- a/tests/looping.rs
+++ b/tests/looping.rs
@@ -1,12 +1,11 @@
-use rhai::Engine;
+use rhai::{Engine, EvalAltResult};
 
 #[test]
-fn test_loop() {
+fn test_loop() -> Result<(), EvalAltResult> {
     let mut engine = Engine::new();
 
-    assert!(engine
-        .eval::<bool>(
-            "
+    assert!(engine.eval::<bool>(
+        r"
 			let x = 0;
 			let i = 0;
 
@@ -22,6 +21,7 @@ fn test_loop() {
 
 			x == 45
 		"
-        )
-        .unwrap())
+    )?);
+
+    Ok(())
 }
diff --git a/tests/method_call.rs b/tests/method_call.rs
index ee6b3dc0..f9f09652 100644
--- a/tests/method_call.rs
+++ b/tests/method_call.rs
@@ -1,8 +1,7 @@
-use rhai::Engine;
-use rhai::RegisterFn;
+use rhai::{Engine, EvalAltResult, RegisterFn};
 
 #[test]
-fn test_method_call() {
+fn test_method_call() -> Result<(), EvalAltResult> {
     #[derive(Clone)]
     struct TestStruct {
         x: i64,
@@ -25,9 +24,9 @@ fn test_method_call() {
     engine.register_fn("update", TestStruct::update);
     engine.register_fn("new_ts", TestStruct::new);
 
-    if let Ok(result) = engine.eval::<TestStruct>("let x = new_ts(); x.update(); x") {
-        assert_eq!(result.x, 1001);
-    } else {
-        assert!(false);
-    }
+    let ts = engine.eval::<TestStruct>("let x = new_ts(); x.update(); x")?;
+
+    assert_eq!(ts.x, 1001);
+
+    Ok(())
 }
diff --git a/tests/mismatched_op.rs b/tests/mismatched_op.rs
index 944051d7..314ea378 100644
--- a/tests/mismatched_op.rs
+++ b/tests/mismatched_op.rs
@@ -4,12 +4,12 @@ use rhai::{Engine, EvalAltResult, RegisterFn};
 fn test_mismatched_op() {
     let mut engine = Engine::new();
 
-    assert_eq!(
-        engine.eval::<i64>("60 + \"hello\""),
-        Err(EvalAltResult::ErrorMismatchOutputType(
-            "alloc::string::String".into()
-        ))
-    );
+    let r = engine.eval::<i64>("60 + \"hello\"");
+
+    match r {
+        Err(EvalAltResult::ErrorMismatchOutputType(err, _)) if err == "alloc::string::String" => (),
+        _ => panic!(),
+    }
 }
 
 #[test]
@@ -29,10 +29,14 @@ fn test_mismatched_op_custom_type() {
     engine.register_type::<TestStruct>();
     engine.register_fn("new_ts", TestStruct::new);
 
-    assert_eq!(
-        engine.eval::<i64>("60 + new_ts()"),
-        Err(EvalAltResult::ErrorFunctionNotFound(
-            "+ (i64, mismatched_op::test_mismatched_op_custom_type::TestStruct)".into()
-        ))
-    );
+    let r = engine.eval::<i64>("60 + new_ts()");
+
+    match r {
+        Err(EvalAltResult::ErrorFunctionNotFound(err, _))
+            if err == "+ (i64, mismatched_op::test_mismatched_op_custom_type::TestStruct)" =>
+        {
+            ()
+        }
+        _ => panic!(),
+    }
 }
diff --git a/tests/not.rs b/tests/not.rs
index 0e6252a3..8bade80a 100644
--- a/tests/not.rs
+++ b/tests/not.rs
@@ -1,16 +1,18 @@
-use rhai::Engine;
+use rhai::{Engine, EvalAltResult};
 
 #[test]
-fn test_not() {
+fn test_not() -> Result<(), EvalAltResult> {
     let mut engine = Engine::new();
 
     assert_eq!(
-        engine.eval::<bool>("let not_true = !true; not_true"),
-        Ok(false)
+        engine.eval::<bool>("let not_true = !true; not_true")?,
+        false
     );
 
-    assert_eq!(engine.eval::<bool>("fn not(x) { !x } not(false)"), Ok(true));
+    assert_eq!(engine.eval::<bool>("fn not(x) { !x } not(false)")?, true);
 
     // TODO - do we allow stacking unary operators directly? e.g '!!!!!!!true'
-    assert_eq!(engine.eval::<bool>("!(!(!(!(true))))"), Ok(true));
+    assert_eq!(engine.eval::<bool>("!(!(!(!(true))))")?, true);
+
+    Ok(())
 }
diff --git a/tests/number_literals.rs b/tests/number_literals.rs
index 05185cb9..16e12719 100644
--- a/tests/number_literals.rs
+++ b/tests/number_literals.rs
@@ -1,35 +1,43 @@
-use rhai::Engine;
+use rhai::{Engine, EvalAltResult};
 
 #[test]
-fn test_number_literal() {
+fn test_number_literal() -> Result<(), EvalAltResult> {
     let mut engine = Engine::new();
 
-    assert_eq!(engine.eval::<i64>("65"), Ok(65));
+    assert_eq!(engine.eval::<i64>("65")?, 65);
+
+    Ok(())
 }
 
 #[test]
-fn test_hex_literal() {
+fn test_hex_literal() -> Result<(), EvalAltResult> {
     let mut engine = Engine::new();
 
-    assert_eq!(engine.eval::<i64>("let x = 0xf; x"), Ok(15));
-    assert_eq!(engine.eval::<i64>("let x = 0xff; x"), Ok(255));
+    assert_eq!(engine.eval::<i64>("let x = 0xf; x")?, 15);
+    assert_eq!(engine.eval::<i64>("let x = 0xff; x")?, 255);
+
+    Ok(())
 }
 
 #[test]
-fn test_octal_literal() {
+fn test_octal_literal() -> Result<(), EvalAltResult> {
     let mut engine = Engine::new();
 
-    assert_eq!(engine.eval::<i64>("let x = 0o77; x"), Ok(63));
-    assert_eq!(engine.eval::<i64>("let x = 0o1234; x"), Ok(668));
+    assert_eq!(engine.eval::<i64>("let x = 0o77; x")?, 63);
+    assert_eq!(engine.eval::<i64>("let x = 0o1234; x")?, 668);
+
+    Ok(())
 }
 
 #[test]
-fn test_binary_literal() {
+fn test_binary_literal() -> Result<(), EvalAltResult> {
     let mut engine = Engine::new();
 
-    assert_eq!(engine.eval::<i64>("let x = 0b1111; x"), Ok(15));
+    assert_eq!(engine.eval::<i64>("let x = 0b1111; x")?, 15);
     assert_eq!(
-        engine.eval::<i64>("let x = 0b0011_1100_1010_0101; x"),
-        Ok(15525)
+        engine.eval::<i64>("let x = 0b0011_1100_1010_0101; x")?,
+        15525
     );
+
+    Ok(())
 }
diff --git a/tests/ops.rs b/tests/ops.rs
index c2f2d241..d1464dfb 100644
--- a/tests/ops.rs
+++ b/tests/ops.rs
@@ -1,19 +1,23 @@
-use rhai::Engine;
+use rhai::{Engine, EvalAltResult};
 
 #[test]
-fn test_ops() {
+fn test_ops() -> Result<(), EvalAltResult> {
     let mut engine = Engine::new();
 
-    assert_eq!(engine.eval::<i64>("60 + 5"), Ok(65));
-    assert_eq!(engine.eval::<i64>("(1 + 2) * (6 - 4) / 2"), Ok(3));
+    assert_eq!(engine.eval::<i64>("60 + 5")?, 65);
+    assert_eq!(engine.eval::<i64>("(1 + 2) * (6 - 4) / 2")?, 3);
+
+    Ok(())
 }
 
 #[test]
-fn test_op_prec() {
+fn test_op_prec() -> Result<(), EvalAltResult> {
     let mut engine = Engine::new();
 
     assert_eq!(
-        engine.eval::<i64>("let x = 0; if x == 10 || true { x = 1} x"),
-        Ok(1)
+        engine.eval::<i64>("let x = 0; if x == 10 || true { x = 1} x")?,
+        1
     );
+
+    Ok(())
 }
diff --git a/tests/power_of.rs b/tests/power_of.rs
index 45211fb6..ac41a611 100644
--- a/tests/power_of.rs
+++ b/tests/power_of.rs
@@ -1,36 +1,34 @@
-use rhai::Engine;
+use rhai::{Engine, EvalAltResult};
 
 #[test]
-fn test_power_of() {
+fn test_power_of() -> Result<(), EvalAltResult> {
     let mut engine = Engine::new();
 
-    assert_eq!(engine.eval::<i64>("2 ~ 3"), Ok(8));
-    assert_eq!(engine.eval::<i64>("(-2 ~ 3)"), Ok(-8));
-    assert_eq!(engine.eval::<f64>("2.2 ~ 3.3"), Ok(13.489468760533386_f64));
-    assert_eq!(engine.eval::<f64>("2.0~-2.0"), Ok(0.25_f64));
-    assert_eq!(engine.eval::<f64>("(-2.0~-2.0)"), Ok(0.25_f64));
-    assert_eq!(engine.eval::<f64>("(-2.0~-2)"), Ok(0.25_f64));
-    assert_eq!(engine.eval::<i64>("4~3"), Ok(64));
+    assert_eq!(engine.eval::<i64>("2 ~ 3")?, 8);
+    assert_eq!(engine.eval::<i64>("(-2 ~ 3)")?, -8);
+    assert_eq!(engine.eval::<f64>("2.2 ~ 3.3")?, 13.489468760533386_f64);
+    assert_eq!(engine.eval::<f64>("2.0~-2.0")?, 0.25_f64);
+    assert_eq!(engine.eval::<f64>("(-2.0~-2.0)")?, 0.25_f64);
+    assert_eq!(engine.eval::<f64>("(-2.0~-2)")?, 0.25_f64);
+    assert_eq!(engine.eval::<i64>("4~3")?, 64);
+
+    Ok(())
 }
 
 #[test]
-fn test_power_of_equals() {
+fn test_power_of_equals() -> Result<(), EvalAltResult> {
     let mut engine = Engine::new();
 
-    assert_eq!(engine.eval::<i64>("let x = 2; x ~= 3; x"), Ok(8));
-    assert_eq!(engine.eval::<i64>("let x = -2; x ~= 3; x"), Ok(-8));
+    assert_eq!(engine.eval::<i64>("let x = 2; x ~= 3; x")?, 8);
+    assert_eq!(engine.eval::<i64>("let x = -2; x ~= 3; x")?, -8);
     assert_eq!(
-        engine.eval::<f64>("let x = 2.2; x ~= 3.3; x"),
-        Ok(13.489468760533386_f64)
+        engine.eval::<f64>("let x = 2.2; x ~= 3.3; x")?,
+        13.489468760533386_f64
     );
-    assert_eq!(
-        engine.eval::<f64>("let x = 2.0; x ~= -2.0; x"),
-        Ok(0.25_f64)
-    );
-    assert_eq!(
-        engine.eval::<f64>("let x = -2.0; x ~= -2.0; x"),
-        Ok(0.25_f64)
-    );
-    assert_eq!(engine.eval::<f64>("let x = -2.0; x ~= -2; x"), Ok(0.25_f64));
-    assert_eq!(engine.eval::<i64>("let x =4; x ~= 3; x"), Ok(64));
+    assert_eq!(engine.eval::<f64>("let x = 2.0; x ~= -2.0; x")?, 0.25_f64);
+    assert_eq!(engine.eval::<f64>("let x = -2.0; x ~= -2.0; x")?, 0.25_f64);
+    assert_eq!(engine.eval::<f64>("let x = -2.0; x ~= -2; x")?, 0.25_f64);
+    assert_eq!(engine.eval::<i64>("let x =4; x ~= 3; x")?, 64);
+
+    Ok(())
 }
diff --git a/tests/string.rs b/tests/string.rs
index 5b819e94..e7df5d05 100644
--- a/tests/string.rs
+++ b/tests/string.rs
@@ -1,15 +1,17 @@
-use rhai::Engine;
+use rhai::{Engine, EvalAltResult};
 
 #[test]
-fn test_string() {
+fn test_string() -> Result<(), EvalAltResult> {
     let mut engine = Engine::new();
 
     assert_eq!(
-        engine.eval::<String>("\"Test string: \\u2764\""),
-        Ok("Test string: ❤".to_string())
+        engine.eval::<String>("\"Test string: \\u2764\"")?,
+        "Test string: ❤".to_string()
     );
     assert_eq!(
-        engine.eval::<String>("\"foo\" + \"bar\""),
-        Ok("foobar".to_string())
+        engine.eval::<String>("\"foo\" + \"bar\"")?,
+        "foobar".to_string()
     );
+
+    Ok(())
 }
diff --git a/tests/unary_after_binary.rs b/tests/unary_after_binary.rs
index 00778e7b..f44111d4 100644
--- a/tests/unary_after_binary.rs
+++ b/tests/unary_after_binary.rs
@@ -1,15 +1,17 @@
-use rhai::Engine;
+use rhai::{Engine, EvalAltResult};
 
 #[test]
 // TODO also add test case for unary after compound
 // Hah, turns out unary + has a good use after all!
-fn test_unary_after_binary() {
+fn test_unary_after_binary() -> Result<(), EvalAltResult> {
     let mut engine = Engine::new();
 
-    assert_eq!(engine.eval::<i64>("10 % +4"), Ok(2));
-    assert_eq!(engine.eval::<i64>("10 << +4"), Ok(160));
-    assert_eq!(engine.eval::<i64>("10 >> +4"), Ok(0));
-    assert_eq!(engine.eval::<i64>("10 & +4"), Ok(0));
-    assert_eq!(engine.eval::<i64>("10 | +4"), Ok(14));
-    assert_eq!(engine.eval::<i64>("10 ^ +4"), Ok(14));
+    assert_eq!(engine.eval::<i64>("10 % +4")?, 2);
+    assert_eq!(engine.eval::<i64>("10 << +4")?, 160);
+    assert_eq!(engine.eval::<i64>("10 >> +4")?, 0);
+    assert_eq!(engine.eval::<i64>("10 & +4")?, 0);
+    assert_eq!(engine.eval::<i64>("10 | +4")?, 14);
+    assert_eq!(engine.eval::<i64>("10 ^ +4")?, 14);
+
+    Ok(())
 }
diff --git a/tests/unary_minus.rs b/tests/unary_minus.rs
index 49701bcb..b32e6860 100644
--- a/tests/unary_minus.rs
+++ b/tests/unary_minus.rs
@@ -1,10 +1,12 @@
-use rhai::Engine;
+use rhai::{Engine, EvalAltResult};
 
 #[test]
-fn test_unary_minus() {
+fn test_unary_minus() -> Result<(), EvalAltResult> {
     let mut engine = Engine::new();
 
-    assert_eq!(engine.eval::<i64>("let x = -5; x"), Ok(-5));
-    assert_eq!(engine.eval::<i64>("fn n(x) { -x } n(5)"), Ok(-5));
-    assert_eq!(engine.eval::<i64>("5 - -(-5)"), Ok(0));
+    assert_eq!(engine.eval::<i64>("let x = -5; x")?, -5);
+    assert_eq!(engine.eval::<i64>("fn n(x) { -x } n(5)")?, -5);
+    assert_eq!(engine.eval::<i64>("5 - -(-5)")?, 0);
+
+    Ok(())
 }
diff --git a/tests/unit.rs b/tests/unit.rs
index 7283b70b..5f54bb15 100644
--- a/tests/unit.rs
+++ b/tests/unit.rs
@@ -1,25 +1,22 @@
-use rhai::Engine;
+use rhai::{Engine, EvalAltResult};
 
 #[test]
-fn test_unit() {
+fn test_unit() -> Result<(), EvalAltResult> {
     let mut engine = Engine::new();
-
-    assert_eq!(engine.eval::<()>("let x = (); x"), Ok(()));
+    assert_eq!(engine.eval::<()>("let x = (); x")?, ());
+    Ok(())
 }
 
 #[test]
-fn test_unit_eq() {
+fn test_unit_eq() -> Result<(), EvalAltResult> {
     let mut engine = Engine::new();
-
-    assert_eq!(
-        engine.eval::<bool>("let x = (); let y = (); x == y"),
-        Ok(true)
-    );
+    assert_eq!(engine.eval::<bool>("let x = (); let y = (); x == y")?, true);
+    Ok(())
 }
 
 #[test]
-fn test_unit_with_spaces() {
+fn test_unit_with_spaces() -> Result<(), EvalAltResult> {
     let mut engine = Engine::new();
-
-    assert_eq!(engine.eval::<()>("let x = ( ); x"), Ok(()));
+    assert_eq!(engine.eval::<()>("let x = ( ); x")?, ());
+    Ok(())
 }
diff --git a/tests/var_scope.rs b/tests/var_scope.rs
index e802caa3..6b378299 100644
--- a/tests/var_scope.rs
+++ b/tests/var_scope.rs
@@ -1,28 +1,16 @@
-use rhai::{Engine, Scope};
+use rhai::{Engine, EvalAltResult, Scope};
 
 #[test]
-fn test_var_scope() {
+fn test_var_scope() -> Result<(), EvalAltResult> {
     let mut engine = Engine::new();
     let mut scope = Scope::new();
 
-    assert_eq!(
-        engine.eval_with_scope::<()>(&mut scope, "let x = 4 + 5"),
-        Ok(())
-    );
+    engine.eval_with_scope::<()>(&mut scope, "let x = 4 + 5")?;
+    assert_eq!(engine.eval_with_scope::<i64>(&mut scope, "x")?, 9);
+    engine.eval_with_scope::<()>(&mut scope, "x = x + 1; x = x + 2;")?;
+    assert_eq!(engine.eval_with_scope::<i64>(&mut scope, "x")?, 12);
+    assert_eq!(engine.eval_with_scope::<()>(&mut scope, "{let x = 3}")?, ());
+    assert_eq!(engine.eval_with_scope::<i64>(&mut scope, "x")?, 12);
 
-    assert_eq!(engine.eval_with_scope::<i64>(&mut scope, "x"), Ok(9));
-
-    assert_eq!(
-        engine.eval_with_scope::<()>(&mut scope, "x = x + 1; x = x + 2;"),
-        Ok(())
-    );
-
-    assert_eq!(engine.eval_with_scope::<i64>(&mut scope, "x"), Ok(12));
-
-    assert_eq!(
-        engine.eval_with_scope::<()>(&mut scope, "{let x = 3}"),
-        Ok(())
-    );
-
-    assert_eq!(engine.eval_with_scope::<i64>(&mut scope, "x"), Ok(12));
+    Ok(())
 }
diff --git a/tests/while_loop.rs b/tests/while_loop.rs
index 3cbba708..8dc1ae85 100644
--- a/tests/while_loop.rs
+++ b/tests/while_loop.rs
@@ -1,14 +1,16 @@
-use rhai::Engine;
+use rhai::{Engine, EvalAltResult};
 
 #[test]
-fn test_while() {
+fn test_while() -> Result<(), EvalAltResult> {
     let mut engine = Engine::new();
 
     assert_eq!(
         engine.eval::<i64>(
             "let x = 0; while x < 10 { x = x + 1; if x > 5 { \
              break } } x",
-        ),
-        Ok(6)
+        )?,
+        6
     );
+
+    Ok(())
 }