7531 - checking fake screens

This uncovers two open issues:
* incrementing the cursor after drawing a single grapheme
* needing to clear background pixels when drawing a grapheme

1 files changed, 145 insertions, 0 deletions

diff --git a/baremetal/504test-screen.mu b/baremetal/504test-screen.mu
new file mode 100644
index 00000000..428d172c
--- /dev/null
+++ b/baremetal/504test-screen.mu
@@ -0,0 +1,145 @@
+# Some primitives for checking the state of fake screen objects.
+
+# validate data on screen regardless of attributes (color, bold, etc.)
+# Mu doesn't have multi-line strings, so we provide functions for rows or portions of rows.
+# Tab characters (that translate into multiple screen cells) not supported.
+
+fn check-screen-row screen: (addr screen), y: int, expected: (addr array byte), msg: (addr array byte) {
+  check-screen-row-from screen, y, 1, expected, msg
+}
+
+fn check-screen-row-from screen-on-stack: (addr screen), x: int, y: int, expected: (addr array byte), msg: (addr array byte) {
+  var screen/esi: (addr screen) <- copy screen-on-stack
+  var idx/ecx: int <- screen-cell-index screen, y, x
+  # compare 'expected' with the screen contents starting at 'idx', grapheme by grapheme
+  var e: (stream byte 0x100)
+  var e-addr/edx: (addr stream byte) <- address e
+  write e-addr, expected
+  {
+    var done?/eax: boolean <- stream-empty? e-addr
+    compare done?, 0
+    break-if-!=
+    var _g/eax: grapheme <- screen-grapheme-at-idx screen, idx
+    var g/ebx: grapheme <- copy _g
+    var expected-grapheme/eax: grapheme <- read-grapheme e-addr
+    # compare graphemes
+    $check-screen-row-from:compare-graphemes: {
+      # if expected-grapheme is space, null grapheme is also ok
+      {
+        compare expected-grapheme, 0x20
+        break-if-!=
+        compare g, 0
+        break-if-= $check-screen-row-from:compare-graphemes
+      }
+      # if (g == expected-grapheme) print "."
+      compare g, expected-grapheme
+      {
+        break-if-!=
+        draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0, ".", 3  # 3=cyan
+        break $check-screen-row-from:compare-graphemes
+      }
+      # otherwise print an error
+      draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0, msg, 3  # 3=cyan
+      draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0, ": expected '", 3
+      draw-grapheme-at-cursor 0, expected-grapheme, 3
+      draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0, "' at (", 3
+      draw-int32-hex-wrapping-right-then-down-from-cursor-over-full-screen 0, x, 3
+      draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0, ", ", 3
+      draw-int32-hex-wrapping-right-then-down-from-cursor-over-full-screen 0, y, 3
+      draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0, ") but observed '", 3
+      draw-grapheme-at-cursor 0, g, 3
+      draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0, "'", 3
+    }
+    idx <- increment
+    increment x
+    loop
+  }
+}
+
+# various variants by screen-cell attribute; spaces in the 'expected' data should not match the attribute
+
+fn check-screen-row-in-color screen: (addr screen), fg: int, y: int, expected: (addr array byte), msg: (addr array byte) {
+  check-screen-row-in-color-from screen, fg, y, 1, expected, msg
+}
+
+fn check-screen-row-in-color-from screen-on-stack: (addr screen), fg: int, y: int, x: int, expected: (addr array byte), msg: (addr array byte) {
+  var screen/esi: (addr screen) <- copy screen-on-stack
+  var idx/ecx: int <- screen-cell-index screen, y, x
+  # compare 'expected' with the screen contents starting at 'idx', grapheme by grapheme
+  var e: (stream byte 0x100)
+  var e-addr/edx: (addr stream byte) <- address e
+  write e-addr, expected
+  {
+    var done?/eax: boolean <- stream-empty? e-addr
+    compare done?, 0
+    break-if-!=
+    var _g/eax: grapheme <- screen-grapheme-at-idx screen, idx
+    var g/ebx: grapheme <- copy _g
+    var _expected-grapheme/eax: grapheme <- read-grapheme e-addr
+    var expected-grapheme/edi: grapheme <- copy _expected-grapheme
+    $check-screen-row-in-color-from:compare-cells: {
+      # if expected-grapheme is space, null grapheme is also ok
+      {
+        compare expected-grapheme, 0x20
+        break-if-!=
+        compare g, 0
+        break-if-= $check-screen-row-in-color-from:compare-cells
+      }
+      # if expected-grapheme is space, a different color is ok
+      {
+        compare expected-grapheme, 0x20
+        break-if-!=
+        var color/eax: int <- screen-color-at-idx screen, idx
+        compare color, fg
+        break-if-!= $check-screen-row-in-color-from:compare-cells
+      }
+      # compare graphemes
+      $check-screen-row-in-color-from:compare-graphemes: {
+        # if (g == expected-grapheme) print "."
+        compare g, expected-grapheme
+        {
+          break-if-!=
+          draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0, ".", 3  # 3=cyan
+          break $check-screen-row-in-color-from:compare-graphemes
+        }
+        # otherwise print an error
+        draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0, msg, 3  # 3=cyan
+        draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0, ": expected '", 3
+        draw-grapheme-at-cursor 0, expected-grapheme, 3
+        draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0, "' at (", 3
+        draw-int32-hex-wrapping-right-then-down-from-cursor-over-full-screen 0, x, 3
+        draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0, ", ", 3
+        draw-int32-hex-wrapping-right-then-down-from-cursor-over-full-screen 0, y, 3
+        draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0, ") but observed '", 3
+        draw-grapheme-at-cursor 0, g, 3
+        draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0, "'", 3
+      }
+      $check-screen-row-in-color-from:compare-colors: {
+        var color/eax: int <- screen-color-at-idx screen, idx
+        compare fg, color
+        {
+          break-if-!=
+          draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0, ".", 3  # 3=cyan
+          break $check-screen-row-in-color-from:compare-colors
+        }
+        # otherwise print an error
+        draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0, msg, 3  # 3=cyan
+        draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0, ": expected '", 3
+        draw-grapheme-at-cursor 0, expected-grapheme, 3
+        draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0, "' at (", 3
+        draw-int32-hex-wrapping-right-then-down-from-cursor-over-full-screen 0, x, 3
+        draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0, ", ", 3
+        draw-int32-hex-wrapping-right-then-down-from-cursor-over-full-screen 0, y, 3
+        draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0, ") in color ", 3
+        draw-int32-hex-wrapping-right-then-down-from-cursor-over-full-screen 0, fg, 3
+        draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0, " but observed color ", 3
+        draw-int32-hex-wrapping-right-then-down-from-cursor-over-full-screen 0, color, 3
+      }
+    }
+    idx <- increment
+    increment x
+    loop
+  }
+}
+
+