PY-28016 Investigating why the respective test blinks on TC

Added additional info in assertions and also replaced the original cache
data in JSON with a stub containing only Flask required for the test
(otherwise, its initialization seems to slow execution down dramatically).

python/src/com/jetbrains/python/packaging/PyAbstractPackageCache.java

@@ -8,6 +8,7 @@ import com.google.gson.annotations.SerializedName;
 import com.google.gson.reflect.TypeToken;
 import com.intellij.openapi.application.PathManager;
 import com.intellij.openapi.diagnostic.Logger;
+import one.util.streamex.StreamEx;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
@@ -110,6 +111,12 @@ public abstract class PyAbstractPackageCache {
     return packageInfo != null ? packageInfo.getVersions() : null;
   }
 
+  @Override
+  public String toString() {
+    return String.format("%s(size=%d): %s...", getClass().getSimpleName(), myPackages.size(),
+                         StreamEx.ofKeys(myPackages).limit(5).joining(", "));
+  }
+
   protected static class PackageInfo {
     public static final PackageInfo EMPTY = new PackageInfo();
 

python/src/com/jetbrains/python/packaging/PyPIPackageCache.java

@@ -3,6 +3,7 @@ package com.jetbrains.python.packaging;
 
 import com.google.common.annotations.VisibleForTesting;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.TestOnly;
 
 import java.nio.file.Path;
 import java.util.List;
@@ -36,6 +37,11 @@ public class PyPIPackageCache extends PyAbstractPackageCache {
     return ourInstance;
   }
 
+  @TestOnly
+  static synchronized void reset() {
+    ourInstance = null;
+  }
+
   private PyPIPackageCache() {
   }
 

python/testSrc/com/jetbrains/python/packaging/PyPackageCacheTest.java

@@ -16,8 +16,18 @@ public class PyPackageCacheTest extends PyTestCase {
   public void testCaseInsensitivePackageNameMatching() {
     final PyPIPackageCache cache = PyPIPackageCache.getInstance(Paths.get(getTestDataPath(), "pypi-cache.json"));
 
-    assertTrue(cache.containsPackage("flask"));
-    assertTrue(cache.containsPackage("Flask"));
+    assertTrue("Package name in original case is missing: " + cache.toString(), cache.containsPackage("Flask"));
+    assertTrue("Package name in altered case is missing: " + cache.toString(), cache.containsPackage("flask"));
+  }
+
+  @Override
+  protected void tearDown() throws Exception {
+    try {
+      PyPIPackageCache.reset();
+    }
+    finally {
+      super.tearDown();
+    }
   }
 
   @Override