Minimize size of test centos image

src/test/java/com/rapid7/container/analyzer/docker/service/DockerImageAnalyzerServiceTest.java

@@ -38,12 +38,12 @@ public void testAlpine() throws IOException {
   @Test
   public void testCentos() throws IOException {
     // Given
-    File tarFile = new File(getClass().getClassLoader().getResource("containers/test_image_centos.tar").getFile());
-    ImageId expectedId = new ImageId("sha256:48650444e4191276a912ac90816a4ce1e86f76419e004d445a2e42809fec05f7");
-    OperatingSystem expectedOs = new OperatingSystem("Red Hat", "Linux", "Linux", "x86_64", null, "Red Hat Linux");
-    long expectedSize = 201543168;
+    File tarFile = new File(getClass().getClassLoader().getResource("containers/centos/test_image_centos.tar").getFile());
+    ImageId expectedId = new ImageId("sha256:bcbdfe9aa33a028bedc671ecfe56ce628ff64a8ad1b2fa46855c03955fcdc5bf");
+    long expectedSize = 72704;
+    // omit OS check because this image tar was built from scratch
     long expectedLayers = 3;
-    long expectedPackages = 138;
+    long expectedPackages = 1;
 
     // When
     DockerImageAnalyzerService analyzer = new DockerImageAnalyzerService(null);
@@ -52,9 +52,9 @@ public void testCentos() throws IOException {
 
     // Then
     assertEquals(expectedId, image.getId());
-    assertEquals(expectedOs, image.getOperatingSystem());
     assertEquals(expectedSize, image.getSize());
     assertEquals(expectedLayers, image.getLayers().size());
     assertEquals(expectedPackages, image.getPackages().size());
+    assertEquals("A set of system configuration and setup files", image.getPackages().stream().findFirst().get().getDescription());
   }
 }

src/test/resources/containers/centos/Dockerfile

@@ -0,0 +1,13 @@
+FROM docker.io/library/centos:centos6.10
+ARG TMP_RPM="/tmp/rpm"
+RUN mkdir ${TMP_RPM} && \
+  rpm --initdb --dbpath ${TMP_RPM} && \
+  yum remove setup -y -q && \
+  yum install --downloadonly --downloaddir=/tmp setup -y -q && \
+  cd ${TMP_RPM} && \
+  rpm --dbpath ${TMP_RPM} -i ../setup-*.noarch.rpm
+
+FROM scratch
+COPY --from=0 /tmp/rpm/Packages /var/lib/rpm/Packages
+COPY --from=0 /etc/centos-release /etc/os-release
+COPY --from=0 /etc/centos-release /etc/centos-release