Report details about Pillow when running tests

Tests/conftest.py

@@ -0,0 +1,40 @@
+def pytest_report_header(config):
+    import os
+
+    report = []
+
+    def append(*args):
+        report.append(" ".join(args))
+
+    try:
+        from PIL import Image, features
+
+        append("-" * 68)
+        append("Pillow", Image.__version__)
+        append("-" * 68)
+        append("Python modules loaded from", os.path.dirname(Image.__file__))
+        append("Binary modules loaded from", os.path.dirname(Image.core.__file__))
+        append("-" * 68)
+        for name, feature in [
+            ("pil", "PIL CORE"),
+            ("tkinter", "TKINTER"),
+            ("freetype2", "FREETYPE2"),
+            ("littlecms2", "LITTLECMS2"),
+            ("webp", "WEBP"),
+            ("transp_webp", "WEBP Transparency"),
+            ("webp_mux", "WEBPMUX"),
+            ("webp_anim", "WEBP Animation"),
+            ("jpg", "JPEG"),
+            ("jpg_2000", "OPENJPEG (JPEG2000)"),
+            ("zlib", "ZLIB (PNG/ZIP)"),
+            ("libtiff", "LIBTIFF"),
+            ("raqm", "RAQM (Bidirectional Text)"),
+        ]:
+            if features.check(name):
+                append("---", feature, "support ok")
+            else:
+                append("***", feature, "support not installed")
+        append("-" * 68)
+    except Exception as e:
+        return "pytest_report_header failed: %s" % str(e)
+    return "\n".join(report)