tests: Add an a11y test for scales

tests/a11y/Makefile.am

@@ -56,4 +56,5 @@ EXTRA_DIST += \
 	statusbar.ui statusbar.txt \
 	paned.ui paned.txt \
 	iconview.ui iconview.txt \
-	entries.ui entries.txt
+	entries.ui entries.txt \
+	scale-drawvalue.ui scale-drawvalue.txt

tests/a11y/scale-drawvalue.txt

@@ -0,0 +1,25 @@
+window1
+  "frame"
+  index: 0
+  state: enabled resizable sensitive showing visible
+  toolkit: gail
+  <AtkComponent>
+  layer: window
+  alpha: 1
+  scale1
+    "slider"
+    parent: window1
+    index: 0
+    description: -42.0
+    state: enabled focusable horizontal sensitive showing visible
+    toolkit: gail
+    <AtkComponent>
+    layer: widget
+    alpha: 1
+    <AtkAction>
+    action 0 name: activate
+    <AtkValue>
+    minimum value: -100.000000
+    maximum value: 100.000000
+    current value: -42.000000
+    minimum increment: 1.000000

tests/a11y/scale-drawvalue.ui

@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<interface>
+  <!-- interface-requires gtk+ 3.0 -->
+  <object class="GtkAdjustment" id="adjustment1">
+    <property name="lower">-100</property>
+    <property name="upper">100</property>
+    <property name="value">-42</property>
+    <property name="step_increment">1</property>
+    <property name="page_increment">10</property>
+  </object>
+  <object class="GtkWindow" id="window1">
+    <property name="can_focus">False</property>
+    <child>
+      <object class="GtkScale" id="scale1">
+        <property name="width-request">100</property>
+        <property name="visible">True</property>
+        <property name="can_focus">True</property>
+        <property name="adjustment">adjustment1</property>
+        <property name="round_digits">1</property>
+      </object>
+    </child>
+  </object>
+</interface>