Attempt to set valid target extension to uppercase throws an exception

Thanks for the report @Spokje

This should be easy to fix: the setTargetExtension method is not converting to lower the extension passed in before checking against the valid ones.

  /**
   * {@inheritdoc}
   */
  public function setTargetExtension($extension) {
    if ($this->extension) {
      throw new TextimageException("Extension already set");
    }
    if (!in_array($extension, $this->imageFactory->getSupportedExtensions())) {
      $this->logger->error("Unsupported image file extension (%extension) requested.", ['%extension' => $extension]);
      throw new TextimageException("Attempted to set an unsupported file image extension ({$extension})");
    }
    return $this->set('extension', $extension);
  }

Also, would need a test in TextimageApiTest to prevent future regressions.

Patch looks great! Just a few points:

1. You have some whitespace (or tabs?) at the end of the lines. Please remove any trailing space and/or convert tabs to spaces, according to coding standards.

2.

+++ b/src/Tests/TextimageApiTest.php
@@ -197,6 +197,22 @@ class TextimageApiTest extends TextimageTestBase {
+    // Ensure upper-casing in target image file extension is not a reason for exceptions.

This comment is exceeding 80 chars. Please trim exceeding chars and put in a new line.

3.

+++ b/src/Tests/TextimageApiTest.php
@@ -197,6 +197,22 @@ class TextimageApiTest extends TextimageTestBase {
+    $this->assertEqual('image/png', $image->getMimeType());      ¶

You may also want to assert that the file extension of $textimage->getUri() is actually a '.png' (lowercase).

4.

+++ b/src/Textimage.php
@@ -309,7 +309,7 @@ class Textimage implements TextimageInterface {
-    if (!in_array($extension, $this->imageFactory->getSupportedExtensions())) {
+    if (!in_array(strtolower($extension), $this->imageFactory->getSupportedExtensions())) {

Let's do a $extension = strtolower($extension); before the if block, and leave the if untouched. This way we will store the lowercased extension in any case, which is better as in all the image system the extensions are represented lowercase.

Thank you. Last two more things from me then :)

1. +++ b/src/Tests/TextimageApiTest.php
   @@ -197,6 +197,27 @@ class TextimageApiTest extends TextimageTestBase {
   +    // Ensure upper-casing in target image file extension
   +    // is not a reason for exceptions, and upper-cased
   +    // extensions are lowered.
   

   Each line should be as close as possible to 80 chars. I can fix it on commit, do not worry, but just be aware that this is the coding standard and you will find similar remarks especially when you will be proposing patches for Drupal core :)

2. +++ b/src/Tests/TextimageApiTest.php
   @@ -197,6 +197,27 @@ class TextimageApiTest extends TextimageTestBase {
   +    $exploded_textimage_uri = explode('.', $textimage->getUri());
   +    $image_file_extension = array_pop($exploded_textimage_uri);
   

   why not using $image_file_extension = pathinfo($textimage->getUri(), PATHINFO_EXTENSION); instead?

Also, it would be good to include interdiffs in new patches :)

Looks good now, thanks. Setting to RTBC if anyone will have more comments; not much reviews of patches in this module - if no more input in next couple days I will commit this.

Committed. Thank you @Spokje!