diff --git a/src/cryptonum/addition.rs b/src/cryptonum/addition.rs
index c9ad4ea..0484c3b 100644
--- a/src/cryptonum/addition.rs
+++ b/src/cryptonum/addition.rs
@@ -100,66 +100,67 @@ generate_adders!(U4096);
 generate_adders!(U8192);
 generate_adders!(U15360);
 
-#[cfg(test)]
-use testing::run_test;
-#[cfg(test)]
-use cryptonum::Decoder;
-
 macro_rules! generate_tests {
-    ($name: ident, $testname: ident, $modtestname: ident) => (
+    ( $( $name:ident ),* ) => {
         #[cfg(test)]
-        #[test]
-        #[allow(non_snake_case)]
-        fn $testname() {
-            let fname = format!("tests/math/addition{}.test",
-                                stringify!($name));
-            run_test(fname.to_string(), 3, |case| {
-                let (neg0, abytes) = case.get("a").unwrap();
-                let (neg1, bbytes) = case.get("b").unwrap();
-                let (neg2, cbytes) = case.get("c").unwrap();
+        mod normal {
+            use cryptonum::Decoder;
+            use super::*;
+            use testing::run_test;
 
-                assert!(!neg0 && !neg1 && !neg2);
-                let mut a = $name::from_bytes(abytes);
-                let b = $name::from_bytes(bbytes);
-                let c = $name::from_bytes(cbytes);
-                assert_eq!(&a + &b, c);
-                a += b;
-                assert_eq!(a, c);
-            });
+            $(
+                #[test]
+                #[allow(non_snake_case)]
+                fn $name() {
+                    let fname = format!("tests/math/addition{}.test",
+                                        stringify!($name));
+                    run_test(fname.to_string(), 3, |case| {
+                        let (neg0, abytes) = case.get("a").unwrap();
+                        let (neg1, bbytes) = case.get("b").unwrap();
+                        let (neg2, cbytes) = case.get("c").unwrap();
+        
+                        assert!(!neg0 && !neg1 && !neg2);
+                        let mut a = $name::from_bytes(abytes);
+                        let b = $name::from_bytes(bbytes);
+                        let c = $name::from_bytes(cbytes);
+                        assert_eq!(&a + &b, c);
+                        a += b;
+                        assert_eq!(a, c);
+                    });
+                }
+            )*
         }
 
         #[cfg(test)]
-        #[test]
-        #[allow(non_snake_case)]
-        fn $modtestname() {
-            let fname = format!("tests/math/modadd{}.test",
-                                stringify!($name));
-            run_test(fname.to_string(), 4, |case| {
-                let (neg0, abytes) = case.get("a").unwrap();
-                let (neg1, bbytes) = case.get("b").unwrap();
-                let (neg2, cbytes) = case.get("c").unwrap();
-                let (neg3, mbytes) = case.get("m").unwrap();
+        mod slow_modular {
+            use cryptonum::encoding::Decoder;
+            use super::*;
+            use testing::run_test;
 
-                assert!(!neg0 && !neg1 && !neg2 && !neg3);
-                let mut a = $name::from_bytes(abytes);
-                let b = $name::from_bytes(bbytes);
-                let m = $name::from_bytes(mbytes);
-                let c = $name::from_bytes(cbytes);
-                a.modadd(&b, &m);
-                assert_eq!(a, c);
-            });
+            $(
+                #[test]
+                #[allow(non_snake_case)]
+                fn $name() {
+                    let fname = format!("tests/math/modadd{}.test",
+                                        stringify!($name));
+                    run_test(fname.to_string(), 4, |case| {
+                        let (neg0, abytes) = case.get("a").unwrap();
+                        let (neg1, bbytes) = case.get("b").unwrap();
+                        let (neg2, cbytes) = case.get("c").unwrap();
+                        let (neg3, mbytes) = case.get("m").unwrap();
+
+                        assert!(!neg0 && !neg1 && !neg2 && !neg3);
+                        let mut a = $name::from_bytes(abytes);
+                        let b = $name::from_bytes(bbytes);
+                        let m = $name::from_bytes(mbytes);
+                        let c = $name::from_bytes(cbytes);
+                        a.modadd(&b, &m);
+                        assert_eq!(a, c);
+                    });
+                }
+            )*
         }
-    )
+    }
 }
 
-generate_tests!(U192,u192,modU192);
-generate_tests!(U256,u256,modU256);
-generate_tests!(U384,u384,modU384);
-generate_tests!(U512,u512,modU512);
-generate_tests!(U576,u576,modU576);
-generate_tests!(U1024,u1024,modU1024);
-generate_tests!(U2048,u2048,modU2048);
-generate_tests!(U3072,u3072,modU3072);
-generate_tests!(U4096,u4096,modU4096);
-generate_tests!(U8192,u8192,modU8192);
-generate_tests!(U15360,u15360,modU15360);
\ No newline at end of file
+generate_tests!(U192, U256, U384, U512, U576, U1024, U2048, U3072, U4096, U8192, U15360);
\ No newline at end of file
diff --git a/src/cryptonum/division.rs b/src/cryptonum/division.rs
index 89a15f5..2d8e6b5 100644
--- a/src/cryptonum/division.rs
+++ b/src/cryptonum/division.rs
@@ -197,52 +197,54 @@ fn matching_bignum_ge(x: &[u64], y: &[u64]) -> bool
 }
 
 #[cfg(test)]
-use testing::run_test;
-#[cfg(test)]
-use cryptonum::Decoder;
-#[cfg(test)]
-use cryptonum::{U192,U256,U384,U512,U576,U1024,U2048,U3072,U4096,U8192,U15360};
+mod normal {
+    use testing::run_test;
+    use cryptonum::Decoder;
+    use cryptonum::{U192,U256,U384,U512,U576,U1024,
+                    U2048,U3072,U4096,U8192,U15360};
+    use super::*;
 
-macro_rules! generate_tests {
-    ($name: ident, $testname: ident) => (
-        #[cfg(test)]
-        #[test]
-        #[allow(non_snake_case)]
-        fn $testname() {
-            let fname = format!("tests/math/division{}.test",
-                                stringify!($name));
-            run_test(fname.to_string(), 4, |case| {
-                let (neg0, abytes) = case.get("a").unwrap();
-                let (neg1, bbytes) = case.get("b").unwrap();
-                let (neg2, qbytes) = case.get("q").unwrap();
-                let (neg3, rbytes) = case.get("r").unwrap();
+    macro_rules! generate_tests {
+        ($name: ident) => (
+            #[cfg(test)]
+            #[test]
+            #[allow(non_snake_case)]
+            fn $name() {
+                let fname = format!("tests/math/division{}.test",
+                                    stringify!($name));
+                run_test(fname.to_string(), 4, |case| {
+                    let (neg0, abytes) = case.get("a").unwrap();
+                    let (neg1, bbytes) = case.get("b").unwrap();
+                    let (neg2, qbytes) = case.get("q").unwrap();
+                    let (neg3, rbytes) = case.get("r").unwrap();
 
-                assert!(!neg0 && !neg1 && !neg2 && !neg3);
+                    assert!(!neg0 && !neg1 && !neg2 && !neg3);
 
-                let a = $name::from_bytes(abytes);
-                let b = $name::from_bytes(bbytes);
-                let q = $name::from_bytes(qbytes);
-                let r = $name::from_bytes(rbytes);
+                    let a = $name::from_bytes(abytes);
+                    let b = $name::from_bytes(bbytes);
+                    let q = $name::from_bytes(qbytes);
+                    let r = $name::from_bytes(rbytes);
 
-                let mut myq = $name::new();
-                let mut myr = $name::new();
+                    let mut myq = $name::new();
+                    let mut myr = $name::new();
 
-                divmod(&a.values, &b.values, &mut myq.values, &mut myr.values);
-                assert_eq!(q, myq);
-                assert_eq!(r, myr);
-            });
-        }
-    )
-}
+                    divmod(&a.values, &b.values, &mut myq.values, &mut myr.values);
+                    assert_eq!(q, myq);
+                    assert_eq!(r, myr);
+                });
+            }
+        )
+    }
 
-generate_tests!(U192,u192);
-generate_tests!(U256,u256);
-generate_tests!(U384,u384);
-generate_tests!(U512,u512);
-generate_tests!(U576,u576);
-generate_tests!(U1024,u1024);
-generate_tests!(U2048,u2048);
-generate_tests!(U3072,u3072);
-generate_tests!(U4096,u4096);
-generate_tests!(U8192,u8192);
-generate_tests!(U15360,u15360);
\ No newline at end of file
+    generate_tests!(U192);
+    generate_tests!(U256);
+    generate_tests!(U384);
+    generate_tests!(U512);
+    generate_tests!(U576);
+    generate_tests!(U1024);
+    generate_tests!(U2048);
+    generate_tests!(U3072);
+    generate_tests!(U4096);
+    generate_tests!(U8192);
+    generate_tests!(U15360);
+}
\ No newline at end of file
diff --git a/src/cryptonum/subtraction.rs b/src/cryptonum/subtraction.rs
index 6d891c0..923547d 100644
--- a/src/cryptonum/subtraction.rs
+++ b/src/cryptonum/subtraction.rs
@@ -76,45 +76,37 @@ generate_subbers!(U4096);
 generate_subbers!(U8192);
 generate_subbers!(U15360);
 
-#[cfg(test)]
-use testing::run_test;
-#[cfg(test)]
-use cryptonum::Decoder;
-
 macro_rules! generate_tests {
-    ($name: ident, $testname: ident) => (
+    ( $( $name:ident ),* ) => {
         #[cfg(test)]
-        #[test]
-        #[allow(non_snake_case)]
-        fn $testname() {
-            let fname = format!("tests/math/subtraction{}.test",
-                                stringify!($name));
-            run_test(fname.to_string(), 3, |case| {
-                let (neg0, abytes) = case.get("a").unwrap();
-                let (neg1, bbytes) = case.get("b").unwrap();
-                let (neg2, cbytes) = case.get("c").unwrap();
+        mod normal {
+            use cryptonum::Decoder;
+            use super::*;
+            use testing::run_test;
 
-                assert!(!neg0 && !neg1 && !neg2);
-                let mut a = $name::from_bytes(abytes);
-                let b = $name::from_bytes(bbytes);
-                let c = $name::from_bytes(cbytes);
-                let r = &a - &b;
-                assert_eq!(r, c);
-                a -= b;
-                assert_eq!(a, c);
-            });
+            $(
+                #[test]
+                #[allow(non_snake_case)]
+                fn $name() {
+                    let fname = format!("tests/math/subtraction{}.test",
+                                        stringify!($name));
+                    run_test(fname.to_string(), 3, |case| {
+                        let (neg0, abytes) = case.get("a").unwrap();
+                        let (neg1, bbytes) = case.get("b").unwrap();
+                        let (neg2, cbytes) = case.get("c").unwrap();
+        
+                        assert!(!neg0 && !neg1 && !neg2);
+                        let mut a = $name::from_bytes(abytes);
+                        let b = $name::from_bytes(bbytes);
+                        let c = $name::from_bytes(cbytes);
+                        assert_eq!(&a - &b, c);
+                        a -= b;
+                        assert_eq!(a, c);
+                    });
+                }
+            )*
         }
-    )
+    }
 }
 
-generate_tests!(U192,u192);
-generate_tests!(U256,u256);
-generate_tests!(U384,u384);
-generate_tests!(U512,u512);
-generate_tests!(U576,u576);
-generate_tests!(U1024,u1024);
-generate_tests!(U2048,u2048);
-generate_tests!(U3072,u3072);
-generate_tests!(U4096,u4096);
-generate_tests!(U8192,u8192);
-generate_tests!(U15360,u15360);
\ No newline at end of file
+generate_tests!(U192, U256, U384, U512, U576, U1024, U2048, U3072, U4096, U8192, U15360);
\ No newline at end of file