Before patch applied:
* from 0 to 49 -> 100px
* from 50 to 99 -> 50px
* from 100 to 149 -> 100px
* from 140 to 199 -> 150px
* ...

After patch applied:
* 0 -> 100px
* from 1 to 50 -> 50px
* from 51 to 100 -> 100px
* from 101 to 150 -> 150px
from 151 to 200 -> 200px
...
--------------------------------------------------------------------------------

--------------------------------------------------------------------------------
Here's an alternative patch using Float#ceil. Also adds a corresponding test case.

--------------------------------------------------------------------------------

--------------------------------------------------------------------------------
The following error occurred while running tests. Jens, could you check the patch?

<pre>
Failure:
AttachmentsControllerTest#test_thumbnail_should_round_size [/home/ubuntu/redmine-trunk/app/models/attachment.rb:222]:
unexpected invocation: Redmine::Thumbnail.generate("/home/ubuntu/redmine-trunk/test/fixtures/files/2010/11/101123161450_testfile_1.png", "/home/ubuntu/redmine-trunk/tmp/thumbnails/16_8e0294de2441577c529f170b6fb8f638_300.thumb", 300)
unsatisfied expectations:
- expected exactly once, not yet invoked: Redmine::Thumbnail.generate()

bin/rails test test/functional/attachments_controller_test.rb:409
</pre>

This is my environment:
<pre>
Environment:
Redmine version 4.0.0.devel.17734
Ruby version 2.6.0-p-1 (2018-12-06) [x86_64-linux]
Rails version 5.2.2
Environment development
Database adapter SQLite
Mailer queue ActiveJob::QueueAdapters::AsyncAdapter
Mailer delivery smtp
SCM:
Subversion 1.9.3
Mercurial 3.7.3
Cvs 1.12.13
Bazaar 2.7.0
Git 2.7.4
Filesystem
Redmine plugins:
no plugin installed
</pre>
--------------------------------------------------------------------------------
Applying the below patch on top over Jens patch fixes the test.

<pre><code class="diff">
diff --git a/test/unit/attachment_test.rb b/test/unit/attachment_test.rb
index 4bab579..bccb2c6 100644
--- a/test/unit/attachment_test.rb
+++ b/test/unit/attachment_test.rb
@@ -494,7 +494,7 @@ class AttachmentTest < ActiveSupport::TestCase
[101, 150],
].each do |size, generated_size|
thumbnail = attachment.thumbnail(size: size)
- assert_equal "16_8e0294de2441577c529f170b6fb8f638_#{generated_size}.thumb",
+ assert_equal "8e0294de2441577c529f170b6fb8f638_2654_#{generated_size}.thumb",
File.basename(thumbnail)
end
end
</code></pre>

The thumbnail format is @#{digest}_#{filesize}_#{size}.thumb@ where:
* @digest@ is 8e0294de2441577c529f170b6fb8f638
* @filesize@ is 2654
* @size@ is the generated size which changes during the test.
--------------------------------------------------------------------------------
Confirmed that the test passes after applying the patch written by Marius. Setting the target version to 4.1.0.
--------------------------------------------------------------------------------
Committed the patch. Thank you for your contribution.
--------------------------------------------------------------------------------
To fix the tests:

<pre><code class="diff">
diff --git a/test/functional/attachments_controller_test.rb b/test/functional/attachments_controller_test.rb
index cf7e961..faaf462 100644
--- a/test/functional/attachments_controller_test.rb
+++ b/test/functional/attachments_controller_test.rb
@@ -407,7 +407,7 @@ class AttachmentsControllerTest < Redmine::ControllerTest
end

def test_thumbnail_should_round_size
- Redmine::Thumbnail.expects(:generate).with {|source, target, size| size == 250}
+ Redmine::Thumbnail.expects(:generate).with {|source, target, size| size == 300}
</code></pre>
--------------------------------------------------------------------------------
Marius BALTEANU wrote:
> To fix the tests:
>
> [...]

Committed. Thanks.
--------------------------------------------------------------------------------