fix(go): split on \s+ in parseModuleVersions and add unit tests

Use regex whitespace splitting instead of single space to handle
tabs and multiple spaces in go list -m all output. Add unit tests
covering standard lines, replace directives, varied whitespace,
blank lines, malformed input, and duplicate handling.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: a-oren

src/main/java/io/github/guacsec/trustifyda/providers/GoModulesProvider.java

@@ -390,7 +390,8 @@ private Map<String, List<String>> getFinalPackagesVersionsForModule(
   static Map<String, String> parseModuleVersions(String goListOutput) {
     return Arrays.stream(goListOutput.split(Operations.GENERIC_LINE_SEPARATOR))
         .map(String::trim)
-        .map(line -> line.split(" "))
+        .filter(line -> !line.isEmpty())
+        .map(line -> line.split("\\s+"))
         .filter(parts -> parts.length == 2 || (parts.length >= 4 && parts[2].equals("=>")))
         .collect(
             Collectors.toMap(

src/test/java/io/github/guacsec/trustifyda/providers/GoModulesParseModuleVersionsTest.java

@@ -0,0 +1,86 @@
+/*
+ * Copyright 2023-2025 Trustify Dependency Analytics Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.github.guacsec.trustifyda.providers;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.util.Map;
+import org.junit.jupiter.api.Test;
+
+class GoModulesParseModuleVersionsTest {
+
+  @Test
+  void parseStandardModuleLines() {
+    String input = "github.com/foo/bar v1.2.3\ngithub.com/baz/qux v0.1.0\n";
+    Map<String, String> result = GoModulesProvider.parseModuleVersions(input);
+    assertThat(result)
+        .containsEntry("github.com/foo/bar", "v1.2.3")
+        .containsEntry("github.com/baz/qux", "v0.1.0")
+        .hasSize(2);
+  }
+
+  @Test
+  void parseReplaceDirectiveLines() {
+    String input = "github.com/old/mod v1.0.0 => github.com/new/mod v2.0.0\n";
+    Map<String, String> result = GoModulesProvider.parseModuleVersions(input);
+    assertThat(result).containsEntry("github.com/old/mod", "v2.0.0").hasSize(1);
+  }
+
+  @Test
+  void parseWithMultipleSpacesAndTabs() {
+    String input = "github.com/foo/bar   v1.2.3\ngithub.com/baz/qux\tv0.1.0\n";
+    Map<String, String> result = GoModulesProvider.parseModuleVersions(input);
+    assertThat(result)
+        .containsEntry("github.com/foo/bar", "v1.2.3")
+        .containsEntry("github.com/baz/qux", "v0.1.0")
+        .hasSize(2);
+  }
+
+  @Test
+  void parseWithBlankAndWhitespaceOnlyLines() {
+    String input = "\n  \ngithub.com/foo/bar v1.0.0\n\n";
+    Map<String, String> result = GoModulesProvider.parseModuleVersions(input);
+    assertThat(result).containsEntry("github.com/foo/bar", "v1.0.0").hasSize(1);
+  }
+
+  @Test
+  void parseSkipsMalformedLines() {
+    String input = "github.com/foo/bar v1.0.0\nsingle-token\nthree tokens here\n";
+    Map<String, String> result = GoModulesProvider.parseModuleVersions(input);
+    assertThat(result).containsEntry("github.com/foo/bar", "v1.0.0").hasSize(1);
+  }
+
+  @Test
+  void parseEmptyInput() {
+    Map<String, String> result = GoModulesProvider.parseModuleVersions("");
+    assertThat(result).isEmpty();
+  }
+
+  @Test
+  void parseReplaceDirectiveWithTabSeparation() {
+    String input = "github.com/old/mod\tv1.0.0\t=>\tgithub.com/new/mod\tv2.0.0\n";
+    Map<String, String> result = GoModulesProvider.parseModuleVersions(input);
+    assertThat(result).containsEntry("github.com/old/mod", "v2.0.0").hasSize(1);
+  }
+
+  @Test
+  void parseDuplicateModuleKeepsLast() {
+    String input = "github.com/foo/bar v1.0.0\ngithub.com/foo/bar v2.0.0\n";
+    Map<String, String> result = GoModulesProvider.parseModuleVersions(input);
+    assertThat(result).containsEntry("github.com/foo/bar", "v2.0.0").hasSize(1);
+  }
+}