diff --git a/tests/large.rs b/tests/large.rs
new file mode 100644
index 0000000..78a9994
--- /dev/null
+++ b/tests/large.rs
@@ -0,0 +1,242 @@
+//! Large tests that exercise many features at once
+
+#[macro_use]
+mod macros;
+
+test!(
+    /// https://github.com/kaj/rsass/issues/41
+    issue_41,
+    "@function str-replace($string, $search, $replace: \"\") {
+      $index: str-index($string, $search);
+    
+      @if $index {
+        @return str-slice($string, 1, $index - 1)+$replace+str-replace(str-slice($string, $index + str-length($search)), $search, $replace);
+      }
+    
+      @return $index;
+    }
+    
+    $x: str-replace(url(\"a#b#c\"), \"#\", \":\");
+    
+    a {
+      color: $x;
+    }",
+    "a {\n  color: url(\"a:b:;\n}\n"
+);
+
+test!(
+    base64_decode,
+    r##"
+@use "sass:math";
+@use "sass:map";
+
+@function char-at($s, $idx) {
+  @return str-slice($s, $idx, $idx);
+}
+
+@function bitwise-and($a, $b) {
+  $x: null;
+  $y: null;
+
+  @if $a > $b {
+    $x: $a;
+    $y: $b;
+  } @else {
+    $x: $b;
+    $y: $a;
+  }
+
+  $limit: math.floor(math.log($x, 2));
+  $result: 0;
+
+  @for $n from 0 through $limit {
+    $two-pow-n: math.pow(2, $n);
+    $result: $result +
+      $two-pow-n *
+      (math.floor(math.div($x, $two-pow-n)) % 2) *
+      (math.floor(math.div($y, $two-pow-n)) % 2);
+  }
+
+  @return $result;
+}
+
+@function bitwise-shift-left($n, $amt) {
+  @return math.floor($n * math.pow(2, $amt));
+}
+
+@function bitwise-shift-right($n, $amt) {
+  @return math.floor(math.div($n, math.pow(2, $amt)));
+}
+
+@function bitwise-or($a, $b) {
+  $x: null;
+  $y: null;
+
+  @if $a > $b {
+    $x: $a;
+    $y: $b;
+  } @else {
+    $x: $b;
+    $y: $a;
+  }
+
+  $limit: math.floor(math.log($x, 2));
+  $result: 0;
+
+  @for $n from 0 through $limit {
+    $two-pow-n: math.pow(2, $n);
+    $x-div-two-pow-n: math.floor(math.div($x, $two-pow-n)) % 2;
+    $y-div-two-pow-n: math.floor(math.div($y, $two-pow-n)) % 2;
+
+    $result: $result +
+      $two-pow-n *
+      (
+        (
+            ($x-div-two-pow-n + $y-div-two-pow-n) +
+              $x-div-two-pow-n *
+              $y-div-two-pow-n
+          )
+          %
+          2
+      );
+  }
+
+  @return $result;
+}
+
+@function letter-index-map() {
+  $map: ();
+
+  $chars: "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
+
+  @for $i from 1 through str-length($chars) {
+    $char: char-at($chars, $i);
+
+    $map: map.set($map, $char, $i - 1);
+    $map: map.set($map, $i - 1, $char);
+  }
+
+  @return $map;
+}
+
+@function ascii-map() {
+  $map: ();
+
+  $chars-upper: "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
+
+  @for $i from 1 through str-length($chars-upper) {
+    $char: char-at($chars-upper, $i);
+
+    $map: map.set($map, $char, $i - 1 + 65);
+    $map: map.set($map, $i - 1 + 65, $char);
+  }
+
+  $chars-lower: "abcdefghijklmnopqrstuvwxyz";
+
+  @for $i from 1 through str-length($chars-lower) {
+    $char: char-at($chars-lower, $i);
+
+    $map: map.set($map, $char, $i - 1 + 97);
+    $map: map.set($map, $i - 1 + 97, $char);
+  }
+
+  @return $map;
+}
+
+$letter-index-map: letter-index-map();
+$ascii-map: ascii-map();
+
+@function byte-at($str, $idx) {
+  @return map-get($letter-index-map, char-at($str, $idx));
+}
+
+@function chunk-string($str) {
+  $chunks: [];
+
+  @for $i from 1 through str-length($str) {
+    @if ($i - 1) % 4 == 0 {
+      $chunk: byte-at($str, $i)
+        byte-at($str, $i + 1)
+        byte-at($str, $i + 2)
+        byte-at($str, $i + 3);
+
+      $chunks: append($chunks, $chunk);
+    }
+  }
+
+  @return $chunks;
+}
+
+@function decode-base64($str) {
+  $result: "";
+
+  @if str-length($str) % 4 != 0 {
+    @error "Invalid base64 string length";
+  }
+
+  $chunks: chunk-string($str);
+
+  @each $chunk in $chunks {
+    $start: bitwise-or(
+      bitwise-shift-left(nth($chunk, 1), 18),
+      bitwise-shift-left(nth($chunk, 2), 12)
+    );
+
+    @if bitwise-and(nth($chunk, 3), nth($chunk, 4)) == 64 {
+      $result: "#{$result}#{map-get($ascii-map, bitwise-and(bitwise-shift-right($start, 16), 255))}";
+    } @else if nth($chunk, 4) == 64 {
+      $start: bitwise-or($start, bitwise-shift-left(nth($chunk, 3), 6));
+
+      $result: "#{$result}#{map-get($ascii-map, bitwise-and(bitwise-shift-right($start, 16), 255))}";
+      $result: "#{$result}#{map-get($ascii-map, bitwise-and(bitwise-shift-right($start, 8), 255))}";
+    } @else {
+      $val: bitwise-or(bitwise-shift-left(nth($chunk, 3), 6), nth($chunk, 4));
+      $start: bitwise-or($start, $val);
+
+      $result: "#{$result}#{map-get($ascii-map, bitwise-and(bitwise-shift-right($start, 16), 255))}";
+      $result: "#{$result}#{map-get($ascii-map, bitwise-and(bitwise-shift-right($start, 8), 255))}";
+      $result: "#{$result}#{map-get($ascii-map, bitwise-and(bitwise-shift-right($start, 0), 255))}";
+    }
+  }
+
+  @return $result;
+}
+
+a {
+  color: decode-base64("SGVsbG8=");
+}
+  "##,
+    "a {\n  color: \"Hello\";\n}\n"
+);
+
+test!(
+    two_sum,
+    r#"
+@use "sass:map";
+
+@function two-sum($nums, $target) {
+  $map: ();
+
+  @for $i from 1 through length($nums) {
+    $num: nth($nums, $i);
+
+    $diff: $target - $num;
+
+    @if map-get($map, $diff) {
+      @return map-get($map, $diff) - 1 $i - 1;
+    } @else {
+      $map: map.set($map, $num, $i);
+    }
+  }
+
+  @return null;
+}
+
+a {
+  color: two-sum(2 7 11 15, 9);
+  color: two-sum(3 2 4, 6);
+  color: two-sum(3 3, 6);
+  color: two-sum(3 2, 6);
+}"#,
+    "a {\n  color: 0 1;\n  color: 1 2;\n  color: 0 1;\n}\n"
+);
diff --git a/tests/rsass_issues.rs b/tests/rsass_issues.rs
deleted file mode 100644
index 8d8ce3c..0000000
--- a/tests/rsass_issues.rs
+++ /dev/null
@@ -1,26 +0,0 @@
-//! Test cases adapted verbatim from the rsass issue tracker
-//! https://github.com/kaj/rsass/issues?q=is%3Aissue
-
-#[macro_use]
-mod macros;
-
-test!(
-    /// https://github.com/kaj/rsass/issues/41
-    issue_41,
-    "@function str-replace($string, $search, $replace: \"\") {
-      $index: str-index($string, $search);
-    
-      @if $index {
-        @return str-slice($string, 1, $index - 1)+$replace+str-replace(str-slice($string, $index + str-length($search)), $search, $replace);
-      }
-    
-      @return $index;
-    }
-    
-    $x: str-replace(url(\"a#b#c\"), \"#\", \":\");
-    
-    a {
-      color: $x;
-    }",
-    "a {\n  color: url(\"a:b:;\n}\n"
-);