add regression tests for multiline configmap with space

api/krusty/configmaps_test.go

@@ -572,3 +572,71 @@ metadata:
   name: test-k9cc55dfm5
 `)
 }
+
+// regression test for https://github.com/kubernetes-sigs/kustomize/issues/4287
+func TestMultilineDataEndsWithSpace(t *testing.T) {
+	th := kusttest_test.MakeHarness(t)
+	th.WriteK(".", `
+apiVersion: kustomize.config.k8s.io/v1beta1
+kind: Kustomization
+configMapGenerator:
+  - name: config_bla
+    files:
+      - cfg.text=cfg.text
+`)
+	th.WriteF("cfg.text", `bla
+bla
+bla 
+`)
+
+	m := th.Run(".", th.MakeDefaultOptions())
+	th.AssertActualEqualsExpected(
+		m, `apiVersion: v1
+data:
+  cfg.text: "bla\nbla\nbla \n"
+kind: ConfigMap
+metadata:
+  name: config_bla-d6m295b8c5
+`)
+}
+
+// regression test to record the behavior prior to the fix for https://github.com/kubernetes-sigs/kustomize/issues/4287
+// so that the fix does not affect leading and trailing newlines in ConfigMap data
+func TestMultilineDataEndsLeadingAndTrailingNewlines(t *testing.T) {
+	th := kusttest_test.MakeHarness(t)
+	th.WriteK(".", `
+apiVersion: kustomize.config.k8s.io/v1beta1
+kind: Kustomization
+configMapGenerator:
+  - name: config_bla
+    files:
+      - cfg.text=cfg.text
+`)
+	th.WriteF("cfg.text", `
+
+bla
+bla
+bla
+
+
+
+`)
+
+	m := th.Run(".", th.MakeDefaultOptions())
+	th.AssertActualEqualsExpected(
+		m, `apiVersion: v1
+data:
+  cfg.text: |2+
+
+
+    bla
+    bla
+    bla
+
+
+
+kind: ConfigMap
+metadata:
+  name: config_bla-8dm6c68g22
+`)
+}