RIS import takes the wrong date and duplicates abstract (#6272)

* Fixed a bug when "The abstract field is the concatenation of the AB and N2 fields."

* Added test

* Ouch, now I understand the testing system for importing.

* Removed unnecessary imports

CHANGELOG.md

@@ -86,6 +86,7 @@ Note that this project **does not** adhere to [Semantic Versioning](http://semve
 - We fixed an issue where citation styles except the default "Preview" could not be used. [#56220](https://github.com/JabRef/jabref/issues/5622)
 - We fixed an issue where a warning was displayed when the title content is made up of two sentences. [#5832](https://github.com/JabRef/jabref/issues/5832)
 - We fixed an issue where an exception was thrown when adding a save action without a selected formatter in the library properties [#6069](https://github.com/JabRef/jabref/issues/6069)
+- We fixed an issue when an "Abstract field" was duplicating text, when importing from RIS file (Neurons) [#6065](https://github.com/JabRef/jabref/issues/6065)
 
 ### Removed
 

src/main/java/org/jabref/logic/importer/fileformat/RisImporter.java

@@ -199,7 +199,7 @@ public ParserResult importDatabase(BufferedReader reader) throws IOException {
                         String oldAb = fields.get(StandardField.ABSTRACT);
                         if (oldAb == null) {
                             fields.put(StandardField.ABSTRACT, value);
-                        } else {
+                        } else if (!oldAb.equals(value) && !value.isEmpty()) {
                             fields.put(StandardField.ABSTRACT, oldAb + OS.NEWLINE + value);
                         }
                     } else if ("UR".equals(tag) || "L2".equals(tag) || "LK".equals(tag)) {

src/test/resources/org/jabref/logic/importer/fileformat/RisImporterTest9.bib

@@ -0,0 +1,18 @@
+% Encoding: UTF-8
+
+@Article{,
+  author    = {Kriegeskorte, Nikolaus and Storrs, Katherine R.},
+  title     = {Grid Cells for Conceptual Spaces?},
+  doi       = {10.1016/j.neuron.2016.10.006},
+  issn      = {0896-6273},
+  number    = {2},
+  pages     = {280--284},
+  url       = {https://doi.org/10.1016/j.neuron.2016.10.006},
+  volume    = {92},
+  abstract  = {location and direction of movement in 2D physical environments via regularly repeating receptive fields.},
+  comment   = {doi: 10.1016/j.neuron.2016.10.006},
+  journal   = {Neuron},
+  month     = oct,
+  publisher = {Elsevier},
+  year      = {2016},
+}

src/test/resources/org/jabref/logic/importer/fileformat/RisImporterTest9.ris

@@ -0,0 +1,23 @@
+TY  - JOUR
+T1  - Grid Cells for Conceptual Spaces?
+AU  - Kriegeskorte, Nikolaus
+AU  - Storrs, Katherine R.
+Y1  - 2016/10/19
+PY  - 2016
+N1  - doi: 10.1016/j.neuron.2016.10.006
+DO  - 10.1016/j.neuron.2016.10.006
+T2  - Neuron
+JF  - Neuron
+SP  - 280
+EP  - 284
+VL  - 92
+IS  - 2
+PB  - Elsevier
+N2  - location and direction of movement in 2D physical environments via regularly repeating receptive fields.
+AB  - location and direction of movement in 2D physical environments via regularly repeating receptive fields.
+SN  - 0896-6273
+M3  - doi: 10.1016/j.neuron.2016.10.006
+UR  - https://doi.org/10.1016/j.neuron.2016.10.006
+Y2  - 2020/03/04
+ER  -
+