diff --git a/src/symbols.rs b/src/symbols.rs
index 069e23d98..9922bc682 100644
--- a/src/symbols.rs
+++ b/src/symbols.rs
@@ -1,5 +1,7 @@
 use strum::{Display, EnumString};
 
+pub mod line;
+
 pub mod block {
     pub const FULL: &str = "█";
     pub const SEVEN_EIGHTHS: &str = "▉";
@@ -114,127 +116,6 @@ pub mod bar {
     };
 }
 
-pub mod line {
-    pub const VERTICAL: &str = "│";
-    pub const DOUBLE_VERTICAL: &str = "║";
-    pub const THICK_VERTICAL: &str = "┃";
-
-    pub const HORIZONTAL: &str = "─";
-    pub const DOUBLE_HORIZONTAL: &str = "═";
-    pub const THICK_HORIZONTAL: &str = "━";
-
-    pub const TOP_RIGHT: &str = "┐";
-    pub const ROUNDED_TOP_RIGHT: &str = "╮";
-    pub const DOUBLE_TOP_RIGHT: &str = "╗";
-    pub const THICK_TOP_RIGHT: &str = "┓";
-
-    pub const TOP_LEFT: &str = "┌";
-    pub const ROUNDED_TOP_LEFT: &str = "╭";
-    pub const DOUBLE_TOP_LEFT: &str = "╔";
-    pub const THICK_TOP_LEFT: &str = "┏";
-
-    pub const BOTTOM_RIGHT: &str = "┘";
-    pub const ROUNDED_BOTTOM_RIGHT: &str = "╯";
-    pub const DOUBLE_BOTTOM_RIGHT: &str = "╝";
-    pub const THICK_BOTTOM_RIGHT: &str = "┛";
-
-    pub const BOTTOM_LEFT: &str = "└";
-    pub const ROUNDED_BOTTOM_LEFT: &str = "╰";
-    pub const DOUBLE_BOTTOM_LEFT: &str = "╚";
-    pub const THICK_BOTTOM_LEFT: &str = "┗";
-
-    pub const VERTICAL_LEFT: &str = "┤";
-    pub const DOUBLE_VERTICAL_LEFT: &str = "╣";
-    pub const THICK_VERTICAL_LEFT: &str = "┫";
-
-    pub const VERTICAL_RIGHT: &str = "├";
-    pub const DOUBLE_VERTICAL_RIGHT: &str = "╠";
-    pub const THICK_VERTICAL_RIGHT: &str = "┣";
-
-    pub const HORIZONTAL_DOWN: &str = "┬";
-    pub const DOUBLE_HORIZONTAL_DOWN: &str = "╦";
-    pub const THICK_HORIZONTAL_DOWN: &str = "┳";
-
-    pub const HORIZONTAL_UP: &str = "┴";
-    pub const DOUBLE_HORIZONTAL_UP: &str = "╩";
-    pub const THICK_HORIZONTAL_UP: &str = "┻";
-
-    pub const CROSS: &str = "┼";
-    pub const DOUBLE_CROSS: &str = "╬";
-    pub const THICK_CROSS: &str = "╋";
-
-    #[derive(Debug, Clone, Copy, Eq, PartialEq, Hash)]
-    pub struct Set {
-        pub vertical: &'static str,
-        pub horizontal: &'static str,
-        pub top_right: &'static str,
-        pub top_left: &'static str,
-        pub bottom_right: &'static str,
-        pub bottom_left: &'static str,
-        pub vertical_left: &'static str,
-        pub vertical_right: &'static str,
-        pub horizontal_down: &'static str,
-        pub horizontal_up: &'static str,
-        pub cross: &'static str,
-    }
-
-    impl Default for Set {
-        fn default() -> Self {
-            NORMAL
-        }
-    }
-
-    pub const NORMAL: Set = Set {
-        vertical: VERTICAL,
-        horizontal: HORIZONTAL,
-        top_right: TOP_RIGHT,
-        top_left: TOP_LEFT,
-        bottom_right: BOTTOM_RIGHT,
-        bottom_left: BOTTOM_LEFT,
-        vertical_left: VERTICAL_LEFT,
-        vertical_right: VERTICAL_RIGHT,
-        horizontal_down: HORIZONTAL_DOWN,
-        horizontal_up: HORIZONTAL_UP,
-        cross: CROSS,
-    };
-
-    pub const ROUNDED: Set = Set {
-        top_right: ROUNDED_TOP_RIGHT,
-        top_left: ROUNDED_TOP_LEFT,
-        bottom_right: ROUNDED_BOTTOM_RIGHT,
-        bottom_left: ROUNDED_BOTTOM_LEFT,
-        ..NORMAL
-    };
-
-    pub const DOUBLE: Set = Set {
-        vertical: DOUBLE_VERTICAL,
-        horizontal: DOUBLE_HORIZONTAL,
-        top_right: DOUBLE_TOP_RIGHT,
-        top_left: DOUBLE_TOP_LEFT,
-        bottom_right: DOUBLE_BOTTOM_RIGHT,
-        bottom_left: DOUBLE_BOTTOM_LEFT,
-        vertical_left: DOUBLE_VERTICAL_LEFT,
-        vertical_right: DOUBLE_VERTICAL_RIGHT,
-        horizontal_down: DOUBLE_HORIZONTAL_DOWN,
-        horizontal_up: DOUBLE_HORIZONTAL_UP,
-        cross: DOUBLE_CROSS,
-    };
-
-    pub const THICK: Set = Set {
-        vertical: THICK_VERTICAL,
-        horizontal: THICK_HORIZONTAL,
-        top_right: THICK_TOP_RIGHT,
-        top_left: THICK_TOP_LEFT,
-        bottom_right: THICK_BOTTOM_RIGHT,
-        bottom_left: THICK_BOTTOM_LEFT,
-        vertical_left: THICK_VERTICAL_LEFT,
-        vertical_right: THICK_VERTICAL_RIGHT,
-        horizontal_down: THICK_HORIZONTAL_DOWN,
-        horizontal_up: THICK_HORIZONTAL_UP,
-        cross: THICK_CROSS,
-    };
-}
-
 pub mod border {
     use super::line;
 
diff --git a/src/symbols/line.rs b/src/symbols/line.rs
new file mode 100644
index 000000000..1416460f2
--- /dev/null
+++ b/src/symbols/line.rs
@@ -0,0 +1,208 @@
+pub const VERTICAL: &str = "│";
+pub const DOUBLE_VERTICAL: &str = "║";
+pub const THICK_VERTICAL: &str = "┃";
+
+pub const HORIZONTAL: &str = "─";
+pub const DOUBLE_HORIZONTAL: &str = "═";
+pub const THICK_HORIZONTAL: &str = "━";
+
+pub const TOP_RIGHT: &str = "┐";
+pub const ROUNDED_TOP_RIGHT: &str = "╮";
+pub const DOUBLE_TOP_RIGHT: &str = "╗";
+pub const THICK_TOP_RIGHT: &str = "┓";
+
+pub const TOP_LEFT: &str = "┌";
+pub const ROUNDED_TOP_LEFT: &str = "╭";
+pub const DOUBLE_TOP_LEFT: &str = "╔";
+pub const THICK_TOP_LEFT: &str = "┏";
+
+pub const BOTTOM_RIGHT: &str = "┘";
+pub const ROUNDED_BOTTOM_RIGHT: &str = "╯";
+pub const DOUBLE_BOTTOM_RIGHT: &str = "╝";
+pub const THICK_BOTTOM_RIGHT: &str = "┛";
+
+pub const BOTTOM_LEFT: &str = "└";
+pub const ROUNDED_BOTTOM_LEFT: &str = "╰";
+pub const DOUBLE_BOTTOM_LEFT: &str = "╚";
+pub const THICK_BOTTOM_LEFT: &str = "┗";
+
+pub const VERTICAL_LEFT: &str = "┤";
+pub const DOUBLE_VERTICAL_LEFT: &str = "╣";
+pub const THICK_VERTICAL_LEFT: &str = "┫";
+
+pub const VERTICAL_RIGHT: &str = "├";
+pub const DOUBLE_VERTICAL_RIGHT: &str = "╠";
+pub const THICK_VERTICAL_RIGHT: &str = "┣";
+
+pub const HORIZONTAL_DOWN: &str = "┬";
+pub const DOUBLE_HORIZONTAL_DOWN: &str = "╦";
+pub const THICK_HORIZONTAL_DOWN: &str = "┳";
+
+pub const HORIZONTAL_UP: &str = "┴";
+pub const DOUBLE_HORIZONTAL_UP: &str = "╩";
+pub const THICK_HORIZONTAL_UP: &str = "┻";
+
+pub const CROSS: &str = "┼";
+pub const DOUBLE_CROSS: &str = "╬";
+pub const THICK_CROSS: &str = "╋";
+
+#[derive(Debug, Clone, Copy, Eq, PartialEq, Hash)]
+pub struct Set {
+    pub vertical: &'static str,
+    pub horizontal: &'static str,
+    pub top_right: &'static str,
+    pub top_left: &'static str,
+    pub bottom_right: &'static str,
+    pub bottom_left: &'static str,
+    pub vertical_left: &'static str,
+    pub vertical_right: &'static str,
+    pub horizontal_down: &'static str,
+    pub horizontal_up: &'static str,
+    pub cross: &'static str,
+}
+
+impl Default for Set {
+    fn default() -> Self {
+        NORMAL
+    }
+}
+
+pub const NORMAL: Set = Set {
+    vertical: VERTICAL,
+    horizontal: HORIZONTAL,
+    top_right: TOP_RIGHT,
+    top_left: TOP_LEFT,
+    bottom_right: BOTTOM_RIGHT,
+    bottom_left: BOTTOM_LEFT,
+    vertical_left: VERTICAL_LEFT,
+    vertical_right: VERTICAL_RIGHT,
+    horizontal_down: HORIZONTAL_DOWN,
+    horizontal_up: HORIZONTAL_UP,
+    cross: CROSS,
+};
+
+pub const ROUNDED: Set = Set {
+    top_right: ROUNDED_TOP_RIGHT,
+    top_left: ROUNDED_TOP_LEFT,
+    bottom_right: ROUNDED_BOTTOM_RIGHT,
+    bottom_left: ROUNDED_BOTTOM_LEFT,
+    ..NORMAL
+};
+
+pub const DOUBLE: Set = Set {
+    vertical: DOUBLE_VERTICAL,
+    horizontal: DOUBLE_HORIZONTAL,
+    top_right: DOUBLE_TOP_RIGHT,
+    top_left: DOUBLE_TOP_LEFT,
+    bottom_right: DOUBLE_BOTTOM_RIGHT,
+    bottom_left: DOUBLE_BOTTOM_LEFT,
+    vertical_left: DOUBLE_VERTICAL_LEFT,
+    vertical_right: DOUBLE_VERTICAL_RIGHT,
+    horizontal_down: DOUBLE_HORIZONTAL_DOWN,
+    horizontal_up: DOUBLE_HORIZONTAL_UP,
+    cross: DOUBLE_CROSS,
+};
+
+pub const THICK: Set = Set {
+    vertical: THICK_VERTICAL,
+    horizontal: THICK_HORIZONTAL,
+    top_right: THICK_TOP_RIGHT,
+    top_left: THICK_TOP_LEFT,
+    bottom_right: THICK_BOTTOM_RIGHT,
+    bottom_left: THICK_BOTTOM_LEFT,
+    vertical_left: THICK_VERTICAL_LEFT,
+    vertical_right: THICK_VERTICAL_RIGHT,
+    horizontal_down: THICK_HORIZONTAL_DOWN,
+    horizontal_up: THICK_HORIZONTAL_UP,
+    cross: THICK_CROSS,
+};
+
+#[cfg(test)]
+mod tests {
+    use indoc::{formatdoc, indoc};
+
+    use super::*;
+
+    #[test]
+    fn default() {
+        assert_eq!(Set::default(), NORMAL);
+    }
+
+    /// A helper function to render a set of symbols.
+    fn render(set: Set) -> String {
+        formatdoc!(
+            "{}{}{}{}
+             {}{}{}{}
+             {}{}{}{}
+             {}{}{}{}",
+            set.top_left,
+            set.horizontal,
+            set.horizontal_down,
+            set.top_right,
+            set.vertical,
+            " ",
+            set.vertical,
+            set.vertical,
+            set.vertical_right,
+            set.horizontal,
+            set.cross,
+            set.vertical_left,
+            set.bottom_left,
+            set.horizontal,
+            set.horizontal_up,
+            set.bottom_right
+        )
+    }
+
+    #[test]
+    fn normal() {
+        assert_eq!(
+            render(NORMAL),
+            indoc!(
+                "┌─┬┐
+                 │ ││
+                 ├─┼┤
+                 └─┴┘"
+            )
+        );
+    }
+
+    #[test]
+    fn rounded() {
+        assert_eq!(
+            render(ROUNDED),
+            indoc!(
+                "╭─┬╮
+                 │ ││
+                 ├─┼┤
+                 ╰─┴╯"
+            )
+        );
+    }
+
+    #[test]
+    fn double() {
+        assert_eq!(
+            render(DOUBLE),
+            indoc!(
+                "╔═╦╗
+                 ║ ║║
+                 ╠═╬╣
+                 ╚═╩╝"
+            )
+        );
+    }
+
+    #[test]
+    fn thick() {
+        assert_eq!(
+            render(THICK),
+            indoc!(
+                "┏━┳┓
+                 ┃ ┃┃
+                 ┣━╋┫
+                 ┗━┻┛"
+            )
+        );
+    }
+}