[pitivi] render: Avoid showing 0 MB estimated size

[Alexandru Băluț <alexbalut src gnome org>]

commit 1823179e5d0d16c62a0ceb81b3f6d766876d9b37
Author: garggaurangi <ggarg276 gmail com>
Date:   Thu Mar 25 23:58:15 2021 +0530

    render: Avoid showing 0 MB estimated size
    
    Fixes #2522

 pitivi/render.py     | 19 ++++++++++---------
 tests/test_render.py | 10 ++++++++++
 2 files changed, 20 insertions(+), 9 deletions(-)
---
diff --git a/pitivi/render.py b/pitivi/render.py
index 3170ca5f2..5e58116f6 100644
--- a/pitivi/render.py
+++ b/pitivi/render.py
@@ -1163,18 +1163,19 @@ class RenderDialog(Loggable):
 
         current_filesize = os.stat(path_from_uri(self.outfile)).st_size
         length = self.project.ges_timeline.props.duration
-        estimated_size = float(
-            current_filesize * float(length) / self.current_position)
+        estimated_size = current_filesize * length / self.current_position
         # Now let's make it human-readable (instead of octets).
         # If it's in the giga range (10⁹) instead of mega (10⁶), use 2 decimals
-        if estimated_size > 10e8:
-            gigabytes = estimated_size / (10 ** 9)
+        gigabytes = estimated_size / (10 ** 9)
+        if gigabytes >= 1:
             return _("%.2f GB") % gigabytes
-        else:
-            megabytes = int(estimated_size / (10 ** 6))
-            if megabytes > 30:
-                megabytes = int(round(megabytes, -1))  # -1 means round to 10
-            return _("%d MB") % megabytes
+
+        megabytes = int(estimated_size / (10 ** 6))
+        if megabytes == 0:
+            return None
+        elif megabytes > 30:
+            megabytes = int(round(megabytes, -1))  # -1 means round to 10
+        return _("%d MB") % megabytes
 
     def _update_filename(self, basename):
         """Updates the filename UI element to show the specified file name."""
diff --git a/tests/test_render.py b/tests/test_render.py
index 2c2d274ef..55ae710d0 100644
--- a/tests/test_render.py
+++ b/tests/test_render.py
@@ -653,3 +653,13 @@ class TestRender(BaseTestMediaLibrary):
         # The audio rate is changed because the default render preset
         # has an audio encoder which does not support 44100.
         self.assertEqual(project.audiorate, 48000)
+
+    def test__get_filesize_estimate(self):
+        project = self.create_simple_project()
+        dialog = self.create_rendering_dialog(project)
+        dialog.current_position = 1
+        from pitivi import render
+        with mock.patch.object(render, "path_from_uri"):
+            with mock.patch("pitivi.render.os.stat") as os_stat:
+                os_stat.return_value.st_size = 0
+                self.assertIsNone(dialog._get_filesize_estimate())