Update bar function (#589)

* fix indexing issue

* [bar] make default output without ansi codes

* [bar] use actual testing framework

sourced/progress_bar/bar.nu

@@ -1,30 +1,32 @@
 # construct bars based of a given percentage from a given width (5 is default)
 # > bar 0.2
 # █
-# > bar 0.71 --width 10
-# ███████
+# > bar 0.71
+# ███▌
 def 'bar' [
     percentage: float
     --background (-b): string = 'default'
     --foreground (-f): string = 'default'
-    --progress (-p) # output the result using 'print -n' with '\r' at the end
+    --progress (-p) # output the result using 'print -n'
     --width (-w): int = 5
 ] {
     let blocks = [null "▏" "▎" "▍" "▌" "▋" "▊" "▉" "█"]
     let $whole_part = (($blocks | last) * ($percentage * $width // 1))
     let $fraction = (
-        $blocks 
+        $blocks
         | get (
-            ($percentage * $width) mod 1 
-            | $in * ($blocks | length) 
-            | math floor
+            ($percentage * $width) mod 1
+            | $in * ($blocks | length | $in - 1)
+            | math round
         )
     )
 
-    let $result = (
-        $"($whole_part)($fraction)" 
-        | fill -c $' ' -w $width 
-        | $"(ansi -e {fg: ($foreground), bg: ($background)})($in)(ansi reset)"
+    let result = (
+        $"($whole_part)($fraction)"
+        | fill -c $' ' -w $width
+        | if ($foreground == 'default') and ($background == 'default') {} else {
+            $"(ansi -e {fg: ($foreground), bg: ($background)})($in)(ansi reset)"
+        }
     )
 
     if $progress {
@@ -34,28 +36,12 @@ def 'bar' [
     }
 }
 
-def assert_eq [num: int, expected: string, input_1: float, input_2?] {
-    let actual = (
-        if ($input_2 == null) {bar $input_1} else {
-            bar $input_1 --width $input_2
-        }
-    )
-    let span = (metadata $expected).span;
-    if $actual != $expected {
-      error make {
-        msg: "Actual != Expected",
-        label: {
-            text: $"expected ($expected) but got ($actual)", start: $span.start, end: $span.end
-        }
-      }
-    } else {
-        print $"Test ($num) (ansi green)passed(ansi reset) ✓"
-    }
-}
+use std assert equal
 
+#[test]
 def bar_tests [] {
-    assert_eq 1 "[49;39m▏    [0m" 0.03
-    assert_eq 2 "[49;39m▎         [0m" 0.03 10
-    assert_eq 3 "[49;39m▊[0m" 0.71 1
-    assert_eq 4 "[49;39m███████   [0m" 0.71 10
-}
+    equal "█▌   " (bar 0.3)
+    equal "███       " (bar 0.3 --width 10)
+    equal "▊" (bar 0.71 --width 1)
+    equal "███████▏  " (bar 0.71 --width 10)
+}