Returning null for unresolved variables

When Blueprints Processor was not able to evaluate a variable, it would
set its value to null.

The expected behaviour would be to set the value to the default repres-
entation in the formal notation as defined by Apache Velocity, which is
a dollar followed by the name of the variable between curly braces. For
example, if the value of the variable pnf-id could not be evaluated in
runtime, its value would be defined as the string "${pnf-id}".

The problem happened during evaluation of the variables that would be
later sent to the template-meshing code for processing.

The fix was to add a check before the value was assigned to the varia-
ble; if the was not null, the assignment will happen normally. Otherwi-
se, if the evaluation resolves to null, the variable receives the defa-
ult value (string "${<variable name>}").

Besides the tests that were put in place to test the code changed for
this fix, two tests were added to the existing test case of the templa-
te meshing code, to act as regression test.

Change-Id: I635afb1eba4c0d45b821811f0119fa6c87ea9542
Issue-ID: CCSDK-1358
Signed-off-by: ottero <rodrigo.ottero@est.tech>

4 files changed, 40 insertions, 1 deletions

diff --git a/ms/controllerblueprints/modules/blueprint-core/src/main/kotlin/org/onap/ccsdk/cds/controllerblueprints/core/service/BluePrintVelocityTemplateService.kt b/ms/controllerblueprints/modules/blueprint-core/src/main/kotlin/org/onap/ccsdk/cds/controllerblueprints/core/service/BluePrintVelocityTemplateService.kt
index 496182ee7..43e6d221f 100644
--- a/ms/controllerblueprints/modules/blueprint-core/src/main/kotlin/org/onap/ccsdk/cds/controllerblueprints/core/service/BluePrintVelocityTemplateService.kt
+++ b/ms/controllerblueprints/modules/blueprint-core/src/main/kotlin/org/onap/ccsdk/cds/controllerblueprints/core/service/BluePrintVelocityTemplateService.kt
@@ -82,4 +82,3 @@ object BluePrintVelocityTemplateService {
 
     }
 }
-
diff --git a/ms/controllerblueprints/modules/blueprint-core/src/test/kotlin/org/onap/ccsdk/cds/controllerblueprints/core/service/BluePrintTemplateServiceTest.kt b/ms/controllerblueprints/modules/blueprint-core/src/test/kotlin/org/onap/ccsdk/cds/controllerblueprints/core/service/BluePrintTemplateServiceTest.kt
index 02505acad..6f961c8ed 100644
--- a/ms/controllerblueprints/modules/blueprint-core/src/test/kotlin/org/onap/ccsdk/cds/controllerblueprints/core/service/BluePrintTemplateServiceTest.kt
+++ b/ms/controllerblueprints/modules/blueprint-core/src/test/kotlin/org/onap/ccsdk/cds/controllerblueprints/core/service/BluePrintTemplateServiceTest.kt
@@ -26,6 +26,7 @@ import org.onap.ccsdk.cds.controllerblueprints.core.utils.BluePrintMetadataUtils
 import org.onap.ccsdk.cds.controllerblueprints.core.utils.JacksonUtils
 import org.springframework.test.context.junit4.SpringRunner
 import kotlin.test.BeforeTest
+import kotlin.test.assertEquals
 import kotlin.test.assertNotNull
 
 @RunWith(SpringRunner::class)
@@ -97,5 +98,39 @@ class BluePrintTemplateServiceTest {
             assertNotNull(content, "failed to generate content for velocity template")
         }
     }
+
+    @Test
+    fun `no value variable should evaluate to default value - standalone template mesh test`() {
+        runBlocking {
+            val template = JacksonUtils.getClassPathFileContent("templates/default-variable-value-velocity-template.vtl")
+            val json = JacksonUtils.getClassPathFileContent("templates/default-variable-value-data.json")
+
+            val content = BluePrintVelocityTemplateService.generateContent(template, json)
+            //first line represents a variable whose value was successfully retrieved, second line contains a variable
+            // whose value could not be evaluated
+            val expected = "sample-hostname\n\${node0_backup_router_address}"
+            assertEquals(expected, content, "No value variable should use default value")
+        }
+    }
+
+    @Test
+    fun `no value variable should evaluate to default value - blueprint processing test`() {
+        runBlocking {
+            val bluePrintTemplateService = BluePrintTemplateService()
+
+            val templateFile = "templates/default-variable-value-velocity-template.vtl"
+            val jsonFile = "templates/default-variable-value-data.json"
+
+            val content = bluePrintTemplateService.generateContentFromFiles(templateFile,
+                    BluePrintConstants.ARTIFACT_VELOCITY_TYPE_NAME, jsonFile, false, mutableMapOf())
+
+            //first line represents a variable whose value was successfully retrieved, second line contains a variable
+            // whose value could not be evaluated
+            val expected = "sample-hostname\n\${node0_backup_router_address}"
+            assertEquals(expected, content, "No value variable should use default value")
+        }
+
+    }
+
 }
 
diff --git a/ms/controllerblueprints/modules/blueprint-core/src/test/resources/templates/default-variable-value-data.json b/ms/controllerblueprints/modules/blueprint-core/src/test/resources/templates/default-variable-value-data.json
new file mode 100755
index 000000000..940ca8d73
--- /dev/null
+++ b/ms/controllerblueprints/modules/blueprint-core/src/test/resources/templates/default-variable-value-data.json
@@ -0,0 +1,3 @@
+{
+  "node0_hostname": "sample-hostname"
+}
diff --git a/ms/controllerblueprints/modules/blueprint-core/src/test/resources/templates/default-variable-value-velocity-template.vtl b/ms/controllerblueprints/modules/blueprint-core/src/test/resources/templates/default-variable-value-velocity-template.vtl
new file mode 100755
index 000000000..ce2458e2e
--- /dev/null
+++ b/ms/controllerblueprints/modules/blueprint-core/src/test/resources/templates/default-variable-value-velocity-template.vtl
@@ -0,0 +1,2 @@
+$node0_hostname
+${node0_backup_router_address}
\ No newline at end of file