[meld] Add tests for syncpoint calculations

[Kai Willadsen <kaiw src gnome org>]

commit 8e6d580221fccf65887fe517f785c43097b30cfd
Author: Kai Willadsen <kai willadsen gmail com>
Date:   Tue Apr 25 11:45:47 2017 +1000

    Add tests for syncpoint calculations

 test/test_misc.py |   33 ++++++++++++++++++++++++++++++++-
 1 files changed, 32 insertions(+), 1 deletions(-)
---
diff --git a/test/test_misc.py b/test/test_misc.py
index 01b5b43..661ee5c 100644
--- a/test/test_misc.py
+++ b/test/test_misc.py
@@ -1,6 +1,6 @@
 
 import pytest
-from meld.misc import merge_intervals
+from meld.misc import calc_syncpoint, merge_intervals
 
 
 @pytest.mark.parametrize("intervals, expected", [
@@ -20,3 +20,34 @@ from meld.misc import merge_intervals
 def test_merge_intervals(intervals, expected):
     merged = merge_intervals(intervals)
     assert merged == expected
+
+
+@pytest.mark.parametrize("value, page_size, lower, upper, expected", [
+    # Boring top
+    (0, 100, 0, 1000, 0.0),
+    # Above the top!
+    (0, 100, 100, 1000, 0.0),
+    # Normal top scaling
+    (25, 100, 0, 1000, 0.25),
+    (50, 100, 0, 1000, 0.5),
+    # Scaling with a lower offset
+    (25, 100, 25, 1000, 0.0),
+    (50, 100, 25, 1000, 0.25),
+    # Somewhere in the middle
+    (500, 100, 0, 1000, 0.5),
+    # Normal bottom scaling
+    (850, 100, 0, 1000, 0.5),
+    (875, 100, 0, 1000, 0.75),
+    # Boring bottom
+    (900, 100, 0, 1000, 1.0),
+    # Below the bottom!
+    (1100, 100, 0, 1000, 1.0),
+])
+def test_calc_syncpoint(value, page_size, lower, upper, expected):
+    import gi
+    gi.require_version("Gtk", "3.0")
+    from gi.repository import Gtk
+    adjustment = Gtk.Adjustment()
+    adjustment.configure(value, lower, upper, 1, 1, page_size)
+    syncpoint = calc_syncpoint(adjustment)
+    assert syncpoint == expected