Allow testing for expected log entries in testNodeSourceEndpoints

This commit adds the required logic to be able to test for
the existence (and absence) of certain log messages
in testNodeSourceEndpoints. As an example, this is implemented
for the tests around excludeUnschedulable.

A side effect of using LogsToBuffer is that tests can't run in
parallel due to the log buffer being shared across all
parallel test cases. As such, these specific tests are now executed
one after another.

Author: Hayajiro

source/node_test.go

@@ -113,6 +113,8 @@ func testNodeSourceEndpoints(t *testing.T) {
 		unschedulable        bool // default to false
 		expected             []*endpoint.Endpoint
 		expectError          bool
+		expectedLogs         []string
+		expectedAbsentLogs   []string
 	}{
 		{
 			title:              "node with short hostname returns one endpoint",
@@ -372,6 +374,9 @@ func testNodeSourceEndpoints(t *testing.T) {
 			unschedulable:        true,
 			excludeUnschedulable: true,
 			expected:             []*endpoint.Endpoint{},
+			expectedLogs: []string{
+				"Skipping node node1 because it is unschedulable",
+			},
 		},
 		{
 			title:                "unschedulable node returns node with excludeUnschedulable=false",
@@ -382,10 +387,15 @@ func testNodeSourceEndpoints(t *testing.T) {
 			expected: []*endpoint.Endpoint{
 				{RecordType: "A", DNSName: "node1", Targets: endpoint.Targets{"1.2.3.4"}},
 			},
+			expectedAbsentLogs: []string{
+				"Skipping node node1 because it is unschedulable",
+			},
 		},
 	} {
 		tc := tc
 		t.Run(tc.title, func(t *testing.T) {
+			buf := testutils.LogsToBuffer(log.DebugLevel, t)
+
 			labelSelector := labels.Everything()
 			if tc.labelSelector != "" {
 				var err error
@@ -434,6 +444,14 @@ func testNodeSourceEndpoints(t *testing.T) {
 
 			// Validate returned endpoints against desired endpoints.
 			validateEndpoints(t, endpoints, tc.expected)
+
+			for _, entry := range tc.expectedLogs {
+				assert.Contains(t, buf.String(), entry)
+			}
+
+			for _, entry := range tc.expectedAbsentLogs {
+				assert.NotContains(t, buf.String(), entry)
+			}
 		})
 	}
 }