diff --git a/io7m-jsycamore-core/src/main/java/com/io7m/jsycamore/core/components/SyErrors.java b/io7m-jsycamore-core/src/main/java/com/io7m/jsycamore/core/components/SyErrors.java
index 0d63bf22..fdde9fde 100644
--- a/io7m-jsycamore-core/src/main/java/com/io7m/jsycamore/core/components/SyErrors.java
+++ b/io7m-jsycamore-core/src/main/java/com/io7m/jsycamore/core/components/SyErrors.java
@@ -17,6 +17,7 @@
 package com.io7m.jsycamore.core.components;
 
 import com.io7m.jnull.NullCheck;
+import com.io7m.junreachable.UnreachableCodeException;
 import org.slf4j.Logger;
 
 /**
@@ -27,7 +28,7 @@ public final class SyErrors
 {
   private SyErrors()
   {
-
+    throw new UnreachableCodeException();
   }
 
   /**
diff --git a/io7m-jsycamore-tests/src/test/java/com/io7m/jsycamore/tests/core/SyThemeTest.java b/io7m-jsycamore-tests/src/test/java/com/io7m/jsycamore/tests/core/SyThemeTest.java
new file mode 100644
index 00000000..a9130668
--- /dev/null
+++ b/io7m-jsycamore-tests/src/test/java/com/io7m/jsycamore/tests/core/SyThemeTest.java
@@ -0,0 +1,60 @@
+/*
+ * Copyright © 2016 <code@io7m.com> http://io7m.com
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
+ * IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+package com.io7m.jsycamore.tests.core;
+
+import com.io7m.jsycamore.core.themes.SyTheme;
+import com.io7m.jsycamore.core.themes.provided.SyThemeBee;
+import com.io7m.jsycamore.core.themes.provided.SyThemeBeeSpecification;
+import com.io7m.jsycamore.core.themes.provided.SyThemeMotive;
+import com.io7m.jsycamore.core.themes.provided.SyThemeMotiveSpecification;
+import com.io7m.jsycamore.core.themes.provided.SyThemeStride;
+import com.io7m.jsycamore.core.themes.provided.SyThemeStrideSpecification;
+import org.junit.Assert;
+import org.junit.Test;
+
+public final class SyThemeTest
+{
+  @Test
+  public void testInstantiateMotive()
+  {
+    final SyTheme t =
+      SyThemeMotive.builder().build();
+    final SyTheme u =
+      SyThemeMotive.builderFrom(SyThemeMotiveSpecification.builder().build()).build();
+    Assert.assertEquals(t, u);
+  }
+
+  @Test
+  public void testInstantiateStride()
+  {
+    final SyTheme t =
+      SyThemeStride.builder().build();
+    final SyTheme u =
+      SyThemeStride.builderFrom(SyThemeStrideSpecification.builder().build()).build();
+    Assert.assertEquals(t, u);
+  }
+
+  @Test
+  public void testInstantiateBee()
+  {
+    final SyTheme t =
+      SyThemeBee.builder().build();
+    final SyTheme u =
+      SyThemeBee.builderFrom(SyThemeBeeSpecification.builder().build()).build();
+    Assert.assertEquals(t, u);
+  }
+}
diff --git a/io7m-jsycamore-tests/src/test/java/com/io7m/jsycamore/tests/core/SyUnreachableTest.java b/io7m-jsycamore-tests/src/test/java/com/io7m/jsycamore/tests/core/SyUnreachableTest.java
new file mode 100644
index 00000000..9a69eaa9
--- /dev/null
+++ b/io7m-jsycamore-tests/src/test/java/com/io7m/jsycamore/tests/core/SyUnreachableTest.java
@@ -0,0 +1,90 @@
+/*
+ * Copyright © 2016 <code@io7m.com> http://io7m.com
+ *  
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *  
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
+ * IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+package com.io7m.jsycamore.tests.core;
+
+import com.io7m.junreachable.UnreachableCodeException;
+import org.junit.Test;
+
+import java.lang.reflect.Constructor;
+import java.lang.reflect.InvocationTargetException;
+
+public final class SyUnreachableTest
+{
+  private static void execNoArgPrivateConstructor(final String name)
+    throws
+    ClassNotFoundException,
+    InstantiationException,
+    IllegalAccessException
+  {
+    try {
+      final Class<?> c = Class.forName(name);
+      final Constructor<?>[] cons = c.getDeclaredConstructors();
+      cons[0].setAccessible(true);
+      cons[0].newInstance();
+    } catch (final InvocationTargetException e) {
+      throw (UnreachableCodeException) e.getCause();
+    }
+  }
+
+  @Test(expected = UnreachableCodeException.class)
+  public void testImageAWT()
+    throws Exception
+  {
+    SyUnreachableTest.execNoArgPrivateConstructor(
+      "com.io7m.jsycamore.core.images.SyImageAWT");
+  }
+
+  @Test(expected = UnreachableCodeException.class)
+  public void testThemeBee()
+    throws Exception
+  {
+    SyUnreachableTest.execNoArgPrivateConstructor(
+      "com.io7m.jsycamore.core.themes.provided.SyThemeBee");
+  }
+
+  @Test(expected = UnreachableCodeException.class)
+  public void testThemeMotive()
+    throws Exception
+  {
+    SyUnreachableTest.execNoArgPrivateConstructor(
+      "com.io7m.jsycamore.core.themes.provided.SyThemeMotive");
+  }
+
+  @Test(expected = UnreachableCodeException.class)
+  public void testThemeStride()
+    throws Exception
+  {
+    SyUnreachableTest.execNoArgPrivateConstructor(
+      "com.io7m.jsycamore.core.themes.provided.SyThemeStride");
+  }
+
+  @Test(expected = UnreachableCodeException.class)
+  public void testThemeDefault()
+    throws Exception
+  {
+    SyUnreachableTest.execNoArgPrivateConstructor(
+      "com.io7m.jsycamore.core.themes.provided.SyThemeDefault");
+  }
+
+  @Test(expected = UnreachableCodeException.class)
+  public void testErrors()
+    throws Exception
+  {
+    SyUnreachableTest.execNoArgPrivateConstructor(
+      "com.io7m.jsycamore.core.components.SyErrors");
+  }
+}