Merge pull request #12955 from vespa-engine/gjoranv/bundle-loader-refactor-and-unit-test

Gjoranv/bundle loader refactor and unit test

9 files changed, 472 insertions, 106 deletions

diff --git a/container-core/src/main/java/com/yahoo/container/core/config/BundleInstaller.java b/container-core/src/main/java/com/yahoo/container/core/config/BundleInstaller.java
new file mode 100644
index 00000000000..fc919571b6c
--- /dev/null
+++ b/container-core/src/main/java/com/yahoo/container/core/config/BundleInstaller.java
@@ -0,0 +1,21 @@
+// Copyright 2020 Oath Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.container.core.config;
+
+import com.yahoo.config.FileReference;
+import com.yahoo.osgi.Osgi;
+import org.osgi.framework.Bundle;
+
+import java.util.List;
+
+/**
+ * @author gjoranv
+ */
+public interface BundleInstaller {
+
+    /**
+     * Installs the bundle with the given file reference, plus all bundles in its X-JDisc-Preinstall-Bundle directive.
+     * Returns all bundles installed to the given OSGi framework as a result of this call.
+     */
+    List<Bundle> installBundles(FileReference reference, Osgi osgi) throws InterruptedException;
+
+}
diff --git a/container-core/src/main/java/com/yahoo/container/core/config/BundleLoader.java b/container-core/src/main/java/com/yahoo/container/core/config/BundleManager.java
index ca11ad387ee..5e9b42a5fda 100644
--- a/container-core/src/main/java/com/yahoo/container/core/config/BundleLoader.java
+++ b/container-core/src/main/java/com/yahoo/container/core/config/BundleManager.java
@@ -1,4 +1,4 @@
-// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+// Copyright 2020 Oath Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.container.core.config;
 
 import com.yahoo.collections.PredicateSplit;
@@ -9,13 +9,12 @@ import com.yahoo.osgi.Osgi;
 import org.osgi.framework.Bundle;
 import org.osgi.framework.wiring.BundleRevision;
 
-import java.io.File;
+import java.util.ArrayList;
 import java.util.HashSet;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
-import java.util.concurrent.TimeUnit;
 import java.util.logging.Logger;
 import java.util.stream.Collectors;
 
@@ -23,12 +22,12 @@ import static com.yahoo.collections.PredicateSplit.partition;
 import static com.yahoo.container.core.BundleLoaderProperties.DISK_BUNDLE_PREFIX;
 
 /**
- * Manages the set of installed 3rd-party component bundles.
+ * Manages the set of installed and active/inactive bundles.
  *
- * @author Tony Vaagenes
  * @author gjoranv
+ * @author Tony Vaagenes
  */
-public class BundleLoader {
+public class BundleManager {
 
     /* Map of file refs of active bundles (not scheduled for uninstall) to a list of all bundles that were installed
      * (pre-install directive) by the bundle pointed to by the file ref (including itself).
@@ -40,20 +39,96 @@ public class BundleLoader {
      */
     private final Map<FileReference, List<Bundle>> reference2Bundles = new LinkedHashMap<>();
 
-    private final Logger log = Logger.getLogger(BundleLoader.class.getName());
+    private final Logger log = Logger.getLogger(BundleManager.class.getName());
     private final Osgi osgi;
 
-    public BundleLoader(Osgi osgi) {
+    // A custom bundle installer for non-disk bundles, to be used for testing
+    private BundleInstaller customBundleInstaller = null;
+
+    public BundleManager(Osgi osgi) {
         this.osgi = osgi;
     }
 
-    private void install(List<FileReference> references) {
+    /**
+     * Installs the given set of bundles and returns the set of bundles that is no longer used
+     * by the application, and should therefore be scheduled for uninstall.
+     */
+    public synchronized Set<Bundle> use(List<FileReference> newFileReferences) {
+        // Must be done before allowing duplicates because allowed duplicates affect osgi.getCurrentBundles
+        Set<Bundle> bundlesToUninstall = getObsoleteBundles(newFileReferences);
+
+        Set<FileReference> obsoleteReferences = getObsoleteFileReferences(newFileReferences);
+        allowDuplicateBundles(obsoleteReferences);
+        removeInactiveFileReferences(obsoleteReferences);
+
+        installBundles(newFileReferences);
+        startBundles();
+
+        bundlesToUninstall.removeAll(allActiveBundles());
+        log.info("Bundles to schedule for uninstall: " + bundlesToUninstall);
+
+        log.info(installedBundlesMessage());
+        return bundlesToUninstall;
+    }
+
+    /**
+     * Returns the bundles that are not assumed to be retained by the new application generation.
+     * Note that at this point we don't yet know the full set of new bundles, because of the potential
+     * pre-install directives in the new bundles. However, only "disk bundles" (file:) can be listed
+     * in the pre-install directive, so we know about all the obsolete application bundles.
+     */
+    private Set<Bundle> getObsoleteBundles(List<FileReference> newReferences) {
+        Set<Bundle> bundlesToRemove = new HashSet<>(osgi.getCurrentBundles());
+
+        for (FileReference fileReferenceToKeep : newReferences) {
+            if (reference2Bundles.containsKey(fileReferenceToKeep)) {
+                bundlesToRemove.removeAll(reference2Bundles.get(fileReferenceToKeep));
+            }
+        }
+        bundlesToRemove.removeAll(osgi.getInitialBundles());
+        return bundlesToRemove;
+    }
+
+
+    private Set<FileReference> getObsoleteFileReferences(List<FileReference> newReferences) {
+        Set<FileReference> obsoleteReferences = new HashSet<>(reference2Bundles.keySet());
+        obsoleteReferences.removeAll(newReferences);
+        return obsoleteReferences;
+    }
+
+    /**
+     * Allow duplicates (bsn+version) for each bundle that corresponds to obsolete file references,
+     * and avoid allowing duplicates for bundles that were installed via the
+     * X-JDisc-Preinstall-Bundle directive. These bundles are always "disk bundles" (library
+     * bundles installed on the node, and not transferred via file distribution).
+     * Such bundles will never have duplicates because they always have the same location id.
+     */
+    private void allowDuplicateBundles(Set<FileReference> obsoleteReferences) {
+        // The bundle at index 0 for each file reference always corresponds to the bundle at the file reference location
+        Set<Bundle> allowedDuplicates = obsoleteReferences.stream()
+                .filter(reference -> ! isDiskBundle(reference))
+                .map(reference -> reference2Bundles.get(reference).get(0))
+                .collect(Collectors.toSet());
+
+        log.info(() -> allowedDuplicates.isEmpty() ? "" : "Adding bundles to allowed duplicates: " + allowedDuplicates);
+        osgi.allowDuplicateBundles(allowedDuplicates);
+    }
+
+    /**
+     * Cleans up the map of active file references
+     */
+    private void removeInactiveFileReferences(Set<FileReference> fileReferencesToRemove) {
+        // Clean up the map of active bundles
+        fileReferencesToRemove.forEach(reference2Bundles::remove);
+    }
+
+    private void installBundles(List<FileReference> references) {
         Set<FileReference> bundlesToInstall = new HashSet<>(references);
 
         // This is just an optimization, as installing a bundle with the same location id returns the already installed bundle.
         bundlesToInstall.removeAll(reference2Bundles.keySet());
 
-        PredicateSplit<FileReference> bundlesToInstall_isDisk = partition(bundlesToInstall, BundleLoader::isDiskBundle);
+        PredicateSplit<FileReference> bundlesToInstall_isDisk = partition(bundlesToInstall, BundleManager::isDiskBundle);
         installBundlesFromDisk(bundlesToInstall_isDisk.trueValues);
         installBundlesFromFileDistribution(bundlesToInstall_isDisk.falseValues);
 
@@ -81,7 +156,9 @@ public class BundleLoader {
             FileAcquirer fileAcquirer = Container.get().getFileAcquirer();
             boolean hasFileDistribution = (fileAcquirer != null);
             if (hasFileDistribution) {
-                installWithFileDistribution(bundlesToInstall, fileAcquirer);
+                installWithFileDistribution(bundlesToInstall, new FileAcquirerBundleInstaller(fileAcquirer));
+            } else if (customBundleInstaller != null) {
+                installWithFileDistribution(bundlesToInstall, customBundleInstaller);
             } else {
                 log.warning("Can't retrieve bundles since file distribution is disabled.");
             }
@@ -89,25 +166,18 @@ public class BundleLoader {
     }
 
     private void installBundleFromDisk(FileReference reference) {
-        assert(reference.value().startsWith(DISK_BUNDLE_PREFIX));
-        String referenceFileName = reference.value().substring(DISK_BUNDLE_PREFIX.length());
         log.info("Installing bundle from disk with reference '" + reference.value() + "'");
 
-        File file = new File(referenceFileName);
-        if ( ! file.exists()) {
-            throw new IllegalArgumentException("Reference '" + reference.value() + "' not found on disk.");
-        }
-
-        List<Bundle> bundles = osgi.install(file.getAbsolutePath());
-
+        var bundleInstaller = new DiskBundleInstaller();
+        List<Bundle> bundles = bundleInstaller.installBundles(reference, osgi);
         reference2Bundles.put(reference, bundles);
     }
 
-    private void installWithFileDistribution(List<FileReference> bundlesToInstall, FileAcquirer fileAcquirer) {
+    private void installWithFileDistribution(List<FileReference> bundlesToInstall, BundleInstaller bundleInstaller) {
         for (FileReference reference : bundlesToInstall) {
             try {
                 log.info("Installing bundle with reference '" + reference.value() + "'");
-                List<Bundle> bundles = obtainBundles(reference, fileAcquirer);
+                List<Bundle> bundles = bundleInstaller.installBundles(reference, osgi);
                 reference2Bundles.put(reference, bundles);
             }
             catch(Exception e) {
@@ -116,11 +186,6 @@ public class BundleLoader {
         }
     }
 
-    private List<Bundle> obtainBundles(FileReference reference, FileAcquirer fileAcquirer) throws InterruptedException {
-        File file = fileAcquirer.waitFor(reference, 7, TimeUnit.DAYS);
-        return osgi.install(file.getAbsolutePath());
-    }
-
     /**
      * Resolves and starts (calls the Bundles BundleActivator) all bundles. Bundle resolution must take place
      * after all bundles are installed to ensure that the framework can resolve dependencies between bundles.
@@ -146,87 +211,12 @@ public class BundleLoader {
         return (bundleRevision.getTypes() & BundleRevision.TYPE_FRAGMENT) != 0;
     }
 
-    /**
-     * Returns the bundles that are not assumed to be retained by the new application generation.
-     * Note that at this point we don't yet know the full set of new bundles, because of the potential
-     * pre-install directives in the new bundles. However, only "disk bundles" (file:) can be listed
-     * in the pre-install directive, so we know about all the obsolete application bundles.
-     */
-    private Set<Bundle> getObsoleteBundles(List<FileReference> newReferences) {
-        Set<Bundle> bundlesToRemove = new HashSet<>(osgi.getCurrentBundles());
-
-        for (FileReference fileReferenceToKeep : newReferences) {
-            if (reference2Bundles.containsKey(fileReferenceToKeep)) {
-                bundlesToRemove.removeAll(reference2Bundles.get(fileReferenceToKeep));
-            }
-        }
-        bundlesToRemove.removeAll(osgi.getInitialBundles());
-        return bundlesToRemove;
-    }
-
-    /**
-     * Cleans up the map of active file references
-     */
-    private void removeInactiveFileReferences(List<FileReference> newReferences) {
-        // Clean up the map of active bundles
-        Set<FileReference> fileReferencesToRemove = getObsoleteFileReferences(newReferences);
-        fileReferencesToRemove.forEach(reference2Bundles::remove);
-    }
-
-
-    /**
-     * Allow duplicates (bsn+version) for each bundle that corresponds to obsolete file references,
-     * and avoid allowing duplicates for bundles that were installed via the
-     * X-JDisc-Preinstall-Bundle directive. These bundles are always "disk bundles" (library
-     * bundles installed on the node, and not transferred via file distribution).
-     * Such bundles will never have duplicates because they always have the same location id.
-     */
-    private void allowDuplicateBundles(List<FileReference> newReferences) {
-        Set<FileReference> obsoleteReferences = getObsoleteFileReferences(newReferences);
-
-        // The bundle at index 0 for each file reference always corresponds to the bundle at the file reference location
-        Set<Bundle> allowedDuplicates = obsoleteReferences.stream()
-                .filter(reference -> ! isDiskBundle(reference))
-                .map(reference -> reference2Bundles.get(reference).get(0))
-                .collect(Collectors.toSet());
-
-        log.info(() -> allowedDuplicates.isEmpty() ? "" : "Adding bundles to allowed duplicates: " + allowedDuplicates);
-        osgi.allowDuplicateBundles(allowedDuplicates);
-    }
-
-    private Set<FileReference> getObsoleteFileReferences(List<FileReference> newReferences) {
-        Set<FileReference> obsoleteReferences = new HashSet<>(reference2Bundles.keySet());
-        obsoleteReferences.removeAll(newReferences);
-        return obsoleteReferences;
-    }
-
     private Set<Bundle> allActiveBundles() {
         return reference2Bundles.keySet().stream()
                 .flatMap(reference -> reference2Bundles.get(reference).stream())
                 .collect(Collectors.toSet());
     }
 
-    /**
-     * Installs the given set of bundles and returns the set of bundles that is no longer used
-     * by the application, and should therefore be scheduled for uninstall.
-     */
-    public synchronized Set<Bundle> use(List<FileReference> newBundles) {
-        // Must be done before allowing duplicates because allowed duplicates affect osgi.getCurrentBundles
-        Set<Bundle> bundlesToUninstall = getObsoleteBundles(newBundles);
-
-        allowDuplicateBundles(newBundles);
-        removeInactiveFileReferences(newBundles);
-
-        install(newBundles);
-        startBundles();
-
-        bundlesToUninstall.removeAll(allActiveBundles());
-        log.info("Bundles to schedule for uninstall: " + bundlesToUninstall);
-
-        log.info(installedBundlesMessage());
-        return bundlesToUninstall;
-    }
-
     private String installedBundlesMessage() {
         StringBuilder sb = new StringBuilder("Installed bundles: {" );
         for (Bundle b : osgi.getBundles())
@@ -236,4 +226,14 @@ public class BundleLoader {
         return sb.toString();
     }
 
+    // Only for testing
+    void useCustomBundleInstaller(BundleInstaller bundleInstaller) {
+        customBundleInstaller = bundleInstaller;
+    }
+
+    // Only for testing
+    List<FileReference> getActiveFileReferences() {
+        return new ArrayList<>(reference2Bundles.keySet());
+    }
+
 }
diff --git a/container-core/src/main/java/com/yahoo/container/core/config/DiskBundleInstaller.java b/container-core/src/main/java/com/yahoo/container/core/config/DiskBundleInstaller.java
new file mode 100644
index 00000000000..3edabe9f861
--- /dev/null
+++ b/container-core/src/main/java/com/yahoo/container/core/config/DiskBundleInstaller.java
@@ -0,0 +1,31 @@
+// Copyright 2020 Oath Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.container.core.config;
+
+import com.yahoo.config.FileReference;
+import com.yahoo.osgi.Osgi;
+import org.osgi.framework.Bundle;
+
+import java.io.File;
+import java.util.List;
+
+import static com.yahoo.container.core.BundleLoaderProperties.DISK_BUNDLE_PREFIX;
+
+/**
+ * @author gjoranv
+ */
+public class DiskBundleInstaller implements BundleInstaller {
+
+    @Override
+    public List<Bundle> installBundles(FileReference reference, Osgi osgi) {
+        assert(reference.value().startsWith(DISK_BUNDLE_PREFIX));
+        String referenceFileName = reference.value().substring(DISK_BUNDLE_PREFIX.length());
+
+        File file = new File(referenceFileName);
+        if ( ! file.exists()) {
+            throw new IllegalArgumentException("Reference '" + reference.value() + "' not found on disk.");
+        }
+
+        return osgi.install(file.getAbsolutePath());
+    }
+
+}
diff --git a/container-core/src/main/java/com/yahoo/container/core/config/FileAcquirerBundleInstaller.java b/container-core/src/main/java/com/yahoo/container/core/config/FileAcquirerBundleInstaller.java
new file mode 100644
index 00000000000..6f6f86a6366
--- /dev/null
+++ b/container-core/src/main/java/com/yahoo/container/core/config/FileAcquirerBundleInstaller.java
@@ -0,0 +1,30 @@
+// Copyright 2020 Oath Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.container.core.config;
+
+import com.yahoo.config.FileReference;
+import com.yahoo.filedistribution.fileacquirer.FileAcquirer;
+import com.yahoo.osgi.Osgi;
+import org.osgi.framework.Bundle;
+
+import java.io.File;
+import java.util.List;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * @author gjoranv
+ */
+public class FileAcquirerBundleInstaller implements BundleInstaller {
+
+    private final FileAcquirer fileAcquirer;
+
+    public FileAcquirerBundleInstaller(FileAcquirer fileAcquirer) {
+        this.fileAcquirer = fileAcquirer;
+    }
+
+    @Override
+    public List<Bundle> installBundles(FileReference reference, Osgi osgi) throws InterruptedException {
+        File file = fileAcquirer.waitFor(reference, 7, TimeUnit.DAYS);
+        return osgi.install(file.getAbsolutePath());
+    }
+
+}
diff --git a/container-core/src/main/java/com/yahoo/container/core/config/HandlersConfigurerDi.java b/container-core/src/main/java/com/yahoo/container/core/config/HandlersConfigurerDi.java
index ef132694e10..d87b38e8b18 100644
--- a/container-core/src/main/java/com/yahoo/container/core/config/HandlersConfigurerDi.java
+++ b/container-core/src/main/java/com/yahoo/container/core/config/HandlersConfigurerDi.java
@@ -9,7 +9,6 @@ import com.yahoo.component.ComponentSpecification;
 import com.yahoo.component.provider.ComponentRegistry;
 import com.yahoo.concurrent.ThreadFactoryFactory;
 import com.yahoo.config.FileReference;
-import com.yahoo.container.core.config.testutil.MockOsgiWrapper;
 import com.yahoo.container.di.ComponentDeconstructor;
 import com.yahoo.container.di.Container;
 import com.yahoo.container.di.componentgraph.core.ComponentGraph;
@@ -82,7 +81,7 @@ public class HandlersConfigurerDi {
                                 OsgiFramework osgiFramework) {
 
         this(subscriberFactory, vespaContainer, configId, deconstructor, discInjector,
-             new ContainerAndDiOsgi(osgiFramework, new BundleLoader(new OsgiImpl(osgiFramework))));
+             new ContainerAndDiOsgi(osgiFramework, new BundleManager(new OsgiImpl(osgiFramework))));
     }
 
     // Only public for testing
@@ -102,9 +101,9 @@ public class HandlersConfigurerDi {
     private static class ContainerAndDiOsgi extends OsgiImpl implements OsgiWrapper {
 
         private final OsgiFramework osgiFramework;
-        private final BundleLoader bundleLoader;
+        private final BundleManager bundleLoader;
 
-        public ContainerAndDiOsgi(OsgiFramework osgiFramework, BundleLoader bundleLoader) {
+        public ContainerAndDiOsgi(OsgiFramework osgiFramework, BundleManager bundleLoader) {
             super(osgiFramework);
             this.osgiFramework = osgiFramework;
             this.bundleLoader = bundleLoader;
diff --git a/container-core/src/test/java/com/yahoo/container/core/config/BundleManagerTest.java b/container-core/src/test/java/com/yahoo/container/core/config/BundleManagerTest.java
new file mode 100644
index 00000000000..414e6b05128
--- /dev/null
+++ b/container-core/src/test/java/com/yahoo/container/core/config/BundleManagerTest.java
@@ -0,0 +1,106 @@
+// Copyright 2020 Oath Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.container.core.config;
+
+import com.yahoo.config.FileReference;
+import org.junit.Before;
+import org.junit.Test;
+import org.osgi.framework.Bundle;
+
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+/**
+ * @author gjoranv
+ */
+public class BundleManagerTest {
+
+    private static final FileReference BUNDLE_1_REF = new FileReference("bundle-1");
+    private static final Bundle BUNDLE_1 = new TestBundle(BUNDLE_1_REF.value());
+    private static final FileReference BUNDLE_2_REF = new FileReference("bundle-2");
+    private static final Bundle BUNDLE_2 = new TestBundle(BUNDLE_2_REF.value());
+
+    private BundleManager bundleLoader;
+    private TestOsgi osgi;
+
+    @Before
+    public void setup() {
+        osgi = new TestOsgi(testBundles());
+        var bundleInstaller = new TestBundleInstaller();
+        bundleLoader = new BundleManager(osgi);
+        bundleLoader.useCustomBundleInstaller(bundleInstaller);
+    }
+
+    @Test
+    public void bundles_are_installed_and_started() {
+        bundleLoader.use(List.of(BUNDLE_1_REF));
+        assertEquals(1, osgi.getInstalledBundles().size());
+
+        // The bundle is installed and started
+        TestBundle installedBundle = (TestBundle)osgi.getInstalledBundles().get(0);
+        assertEquals(BUNDLE_1.getSymbolicName(), installedBundle.getSymbolicName());
+        assertTrue(installedBundle.started);
+
+        // The file reference is active
+        assertEquals(1, bundleLoader.getActiveFileReferences().size());
+        assertEquals(BUNDLE_1_REF, bundleLoader.getActiveFileReferences().get(0));
+    }
+
+    @Test
+    public void new_bundle_can_be_installed_in_reconfig() {
+        bundleLoader.use(List.of(BUNDLE_1_REF));
+        Set<Bundle> obsoleteBundles = bundleLoader.use(List.of(BUNDLE_1_REF, BUNDLE_2_REF));
+
+        // No bundles are obsolete
+        assertTrue(obsoleteBundles.isEmpty());
+
+        // Both bundles are installed
+        assertEquals(2, osgi.getInstalledBundles().size());
+        assertEquals(BUNDLE_1.getSymbolicName(), osgi.getInstalledBundles().get(0).getSymbolicName());
+        assertEquals(BUNDLE_2.getSymbolicName(), osgi.getInstalledBundles().get(1).getSymbolicName());
+
+        // Both bundles are current
+        assertEquals(2, osgi.getCurrentBundles().size());
+        assertEquals(BUNDLE_1.getSymbolicName(), osgi.getCurrentBundles().get(0).getSymbolicName());
+        assertEquals(BUNDLE_2.getSymbolicName(), osgi.getCurrentBundles().get(1).getSymbolicName());
+
+
+        // Both file references are active
+        assertEquals(2, bundleLoader.getActiveFileReferences().size());
+        assertEquals(BUNDLE_1_REF, bundleLoader.getActiveFileReferences().get(0));
+        assertEquals(BUNDLE_2_REF, bundleLoader.getActiveFileReferences().get(1));
+    }
+
+    @Test
+    public void unused_bundle_is_marked_obsolete_after_reconfig() {
+        bundleLoader.use(List.of(BUNDLE_1_REF));
+        Set<Bundle> obsoleteBundles = bundleLoader.use(List.of(BUNDLE_2_REF));
+
+        // The returned set of obsolete bundles contains bundle-1
+        assertEquals(1, obsoleteBundles.size());
+        assertEquals(BUNDLE_1.getSymbolicName(), obsoleteBundles.iterator().next().getSymbolicName());
+
+        // Both bundles are installed
+        assertEquals(2, osgi.getInstalledBundles().size());
+        assertEquals(BUNDLE_1.getSymbolicName(), osgi.getInstalledBundles().get(0).getSymbolicName());
+        assertEquals(BUNDLE_2.getSymbolicName(), osgi.getInstalledBundles().get(1).getSymbolicName());
+
+        // Only bundle-2 is current
+        assertEquals(1, osgi.getCurrentBundles().size());
+        assertEquals(BUNDLE_2.getSymbolicName(), osgi.getCurrentBundles().get(0).getSymbolicName());
+
+        // Only the bundle-2 file reference is active
+        assertEquals(1, bundleLoader.getActiveFileReferences().size());
+        assertEquals(BUNDLE_2_REF, bundleLoader.getActiveFileReferences().get(0));
+    }
+
+
+    private static Map<String, Bundle> testBundles() {
+        return Map.of(BUNDLE_1_REF.value(), BUNDLE_1,
+                      BUNDLE_2_REF.value(), BUNDLE_2);
+    }
+
+}
diff --git a/container-core/src/test/java/com/yahoo/container/core/config/TestBundle.java b/container-core/src/test/java/com/yahoo/container/core/config/TestBundle.java
new file mode 100644
index 00000000000..421f4302c27
--- /dev/null
+++ b/container-core/src/test/java/com/yahoo/container/core/config/TestBundle.java
@@ -0,0 +1,102 @@
+// Copyright 2020 Oath Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.container.core.config;
+
+import com.yahoo.container.bundle.MockBundle;
+import org.osgi.framework.Bundle;
+import org.osgi.framework.Version;
+import org.osgi.framework.wiring.BundleCapability;
+import org.osgi.framework.wiring.BundleRequirement;
+import org.osgi.framework.wiring.BundleRevision;
+import org.osgi.framework.wiring.BundleWiring;
+import org.osgi.resource.Capability;
+import org.osgi.resource.Requirement;
+
+import java.util.List;
+
+/**
+ * @author gjoranv
+ */
+class TestBundle extends MockBundle {
+
+    private static final BundleRevision revision = new TestBundleRevision();
+
+    private final String symbolicName;
+
+    boolean started = false;
+
+    TestBundle(String symbolicName) {
+        this.symbolicName = symbolicName;
+    }
+
+    @Override
+    public void start() {
+        started = true;
+    }
+
+    @Override
+    public String getSymbolicName() {
+        return symbolicName;
+    }
+
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public <T> T adapt(Class<T> type) {
+        if (type.equals(BundleRevision.class)) {
+            return (T) revision;
+        } else {
+            throw new UnsupportedOperationException();
+        }
+    }
+
+
+    static class TestBundleRevision implements BundleRevision {
+
+        // Ensure this is not seen as a fragment bundle.
+        @Override
+        public int getTypes() {
+            return 0;
+        }
+
+        @Override
+        public String getSymbolicName() {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public Version getVersion() {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public List<BundleCapability> getDeclaredCapabilities(String namespace) {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public List<BundleRequirement> getDeclaredRequirements(String namespace) {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public BundleWiring getWiring() {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public List<Capability> getCapabilities(String namespace) {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public List<Requirement> getRequirements(String namespace) {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public Bundle getBundle() {
+            throw new UnsupportedOperationException();
+        }
+    }
+
+}
diff --git a/container-core/src/test/java/com/yahoo/container/core/config/TestBundleInstaller.java b/container-core/src/test/java/com/yahoo/container/core/config/TestBundleInstaller.java
new file mode 100644
index 00000000000..43a5268eabf
--- /dev/null
+++ b/container-core/src/test/java/com/yahoo/container/core/config/TestBundleInstaller.java
@@ -0,0 +1,20 @@
+// Copyright 2020 Oath Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.container.core.config;
+
+import com.yahoo.config.FileReference;
+import com.yahoo.osgi.Osgi;
+import org.osgi.framework.Bundle;
+
+import java.util.List;
+
+/**
+ * @author gjoranv
+ */
+class TestBundleInstaller implements BundleInstaller {
+
+    @Override
+    public List<Bundle> installBundles(FileReference reference, Osgi osgi) {
+        return osgi.install(reference.value());
+    }
+
+}
diff --git a/container-core/src/test/java/com/yahoo/container/core/config/TestOsgi.java b/container-core/src/test/java/com/yahoo/container/core/config/TestOsgi.java
new file mode 100644
index 00000000000..54a3159239c
--- /dev/null
+++ b/container-core/src/test/java/com/yahoo/container/core/config/TestOsgi.java
@@ -0,0 +1,57 @@
+// Copyright 2020 Oath Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.container.core.config;
+
+import com.yahoo.osgi.MockOsgi;
+import org.osgi.framework.Bundle;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * @author gjoranv
+ */
+class TestOsgi extends MockOsgi {
+
+    private final Map<String, Bundle> availableBundles;
+
+    private final List<Bundle> installedBundles = new ArrayList<>();
+    private final List<Bundle> allowedDuplicates = new ArrayList<>();
+
+    TestOsgi(Map<String, Bundle> availableBundles) {
+        this.availableBundles = availableBundles;
+    }
+
+    @Override
+    public List<Bundle> install(String fileReferenceValue) {
+        if (! availableBundles.containsKey(fileReferenceValue))
+            throw new IllegalArgumentException("No such bundle: " + fileReferenceValue);
+
+        Bundle bundle = availableBundles.get(fileReferenceValue);
+        installedBundles.add(bundle);
+        return List.of(bundle);
+    }
+
+    @Override
+    public Bundle[] getBundles() {
+        return installedBundles.toArray(new Bundle[0]);
+    }
+
+    public List<Bundle> getInstalledBundles() {
+        return installedBundles;
+    }
+
+    @Override
+    public List<Bundle> getCurrentBundles() {
+        var currentBundles = new ArrayList<>(installedBundles);
+        currentBundles.removeAll(allowedDuplicates);
+        return currentBundles;
+    }
+
+    @Override
+    public void allowDuplicateBundles(Collection<Bundle> bundles) {
+        allowedDuplicates.addAll(bundles);
+    }
+
+}