SOLR-13812: Add javadocs, uneven rejection and basic test coverage for the SolrTestCaseJ4.params method.

(Diego Ceccarelli, Christine Poerschke, Munendra S N)

solr/CHANGES.txt

@@ -298,6 +298,9 @@ Other Changes
 
 * SOLR-13791: Remove remaining Commons BeanUtils references. (Andras Salamon, Christine Poerschke)
 
+* SOLR-13812: Add javadocs, uneven rejection and basic test coverage for the SolrTestCaseJ4.params method.
+  (Diego Ceccarelli, Christine Poerschke, Munendra S N)
+
 ==================  8.2.0 ==================
 
 Consult the LUCENE_CHANGES.txt file for additional, low level, changes in this release.

solr/core/src/test/org/apache/solr/SolrTestCaseJ4Test.java

@@ -19,6 +19,7 @@ package org.apache.solr;
 import java.io.File;
 
 import org.apache.commons.io.FileUtils;
+import org.apache.solr.common.params.ModifiableSolrParams;
 import org.junit.AfterClass;
 import org.junit.BeforeClass;
 import org.junit.Test;
@@ -61,4 +62,25 @@ public class SolrTestCaseJ4Test extends SolrTestCaseJ4 {
   public void testCorrectCore() throws Exception {
     assertEquals("should be core1", "core1", h.getCore().getName());
   }
+
+  @Test
+  public void testParams() throws Exception {
+    final ModifiableSolrParams params = new ModifiableSolrParams();
+    assertEquals(params.toString(), params().toString());
+
+    params.add("q", "*:*");
+    assertEquals(params.toString(), params("q", "*:*").toString());
+
+    params.add("rows", "42");
+    assertEquals(params.toString(), params("q", "*:*", "rows", "42").toString());
+
+    expectThrows(RuntimeException.class, () -> {
+      params("parameterWithoutValue");
+    });
+
+    expectThrows(RuntimeException.class, () -> {
+      params("q", "*:*", "rows", "42", "parameterWithoutValue");
+    });
+  }
+
 }

solr/test-framework/src/java/org/apache/solr/SolrTestCaseJ4.java

@@ -1270,7 +1270,16 @@ public abstract class SolrTestCaseJ4 extends SolrTestCase {
     return d;
   }
 
+  /**
+   * Generates the correct SolrParams from an even list of strings.
+   * A string in an even position will represent the name of a parameter, while the following string
+   * at position (i+1) will be the assigned value.
+   *
+   * @param params an even list of strings
+   * @return the ModifiableSolrParams generated from the given list of strings.
+   */
   public static ModifiableSolrParams params(String... params) {
+    if (params.length % 2 != 0) throw new RuntimeException("Params length should be even");
     ModifiableSolrParams msp = new ModifiableSolrParams();
     for (int i=0; i<params.length; i+=2) {
       msp.add(params[i], params[i+1]);