diff --git a/sof-js/src/index.js b/sof-js/src/index.js
index c4c4138..120af03 100644
--- a/sof-js/src/index.js
+++ b/sof-js/src/index.js
@@ -266,12 +266,12 @@ export function get_columns(def) {
   return collect_columns([], normalize(structuredClone(def)));
 }
 
-export function evaluate(def, node) {
+export function evaluate(def, node, for_test = true) {
   if (!Array.isArray(node)) {
     return evaluate(def, [node])
   }
 
-  const validation = validate(def);
+  const validation = validate(def, for_test);
   if ((validation.errors || []).length > 0) {
     throw new Error("Incorrect view definition:\n"
       .concat(JSON.stringify(validation.errors, null, 2)));
diff --git a/sof-js/src/validate.js b/sof-js/src/validate.js
index 727decd..dbe4484 100644
--- a/sof-js/src/validate.js
+++ b/sof-js/src/validate.js
@@ -21,113 +21,130 @@ function const_value(name, type = string) {
   };
 }
 
-let viewdef_schema = {
-  $id: "http://hl7.org/fhir/uv/sql-on-fhir/ViewDefinition",
-  title: "ViewDefinition",
-  description: "validate FHIR ViewDefinition schema",
-  type: object,
-  required: ["resource", "select"],
-  additionalProperties: false,
-  properties: {
-    title: string,
-    status: string,
-    resource: identifier,
-    constant: {
-      type: array,
-      minItems: 0,
-      items: {
-        allOf: [
-          {
-            type: object,
-            required: ["name"],
-            properties: { name: string }
-          }, {
-            oneOf: [
-              const_value("valueBase64Binary"),
-              const_value("valueBoolean", bool),
-              const_value("valueCanonical"),
-              const_value("valueCode"),
-              const_value("valueDate"),
-              const_value("valueDateTime"),
-              const_value("valueDecimal", { type: "number" }),
-              const_value("valueId"),
-              const_value("valueInstant"),
-              const_value("valueInteger", { type: "integer" }),
-              const_value("valueInteger64"),
-              const_value("valueOid"),
-              const_value("valueString"),
-              const_value("valuePositiveInt", { type: "integer", minimum: 1 }),
-              const_value("valueTime"),
-              const_value("valueUnsignedInt", { type: "integer", minimum: 0 }),
-              const_value("valueUri"),
-              const_value("valueUrl"),
-              const_value("valueUuid")
-            ]
-          }
-        ]
-      }
-    },
-    select: $ref('select'),
-    where:
-    {
-      type: array,
-      items: {
-        type: object,
-        required: ["path"],
-        additionalProperties: false,
-        properties: {
-          path: fhirpath_string,
-          description: string
+
+function viewdef_schema(for_tests = false) {
+  let column_required_fields
+  let id = "http://hl7.org/fhir/uv/sql-on-fhir/ViewDefinition"
+  if (for_tests) {
+    column_required_fields = ["path", "name", "type"]
+    id = id + "_test"
+  } else {
+    column_required_fields = ["path", "name"]
+  }
+
+  let schema = {
+    $id: id,
+    title: "ViewDefinition",
+    description: "validate FHIR ViewDefinition schema",
+    type: object,
+    required: ["resource", "select"],
+    additionalProperties: false,
+    properties: {
+      title: string,
+      status: string,
+      resourceType: string,
+      name: string,
+      resource: identifier,
+      constant: {
+        type: array,
+        minItems: 0,
+        items: {
+          allOf: [
+            {
+              type: object,
+              required: ["name"],
+              properties: { name: string }
+            }, {
+              oneOf: [
+                const_value("valueBase64Binary"),
+                const_value("valueBoolean", bool),
+                const_value("valueCanonical"),
+                const_value("valueCode"),
+                const_value("valueDate"),
+                const_value("valueDateTime"),
+                const_value("valueDecimal", { type: "number" }),
+                const_value("valueId"),
+                const_value("valueInstant"),
+                const_value("valueInteger", { type: "integer" }),
+                const_value("valueInteger64"),
+                const_value("valueOid"),
+                const_value("valueString"),
+                const_value("valuePositiveInt", { type: "integer", minimum: 1 }),
+                const_value("valueTime"),
+                const_value("valueUnsignedInt", { type: "integer", minimum: 0 }),
+                const_value("valueUri"),
+                const_value("valueUrl"),
+                const_value("valueUuid")
+              ]
+            }
+          ]
         }
-      }
-    }
-  },
-  $defs: {
-    tag: {
-      type: array,
-      items: {
-        type: object,
-        additionalProperties: false,
-        properties: {
-          name: string,
-          value: string
+      },
+      select: $ref('select'),
+      where:
+      {
+        type: array,
+        items: {
+          type: object,
+          required: ["path"],
+          additionalProperties: false,
+          properties: {
+            path: fhirpath_string,
+            description: string
+          }
         }
       }
     },
-    column: {
-      type: array,
-      minItems: 1,
-      items: {
-        type: object,
-        required: ["path", "name", "type"],
-        additionalProperties: false,
-        properties: {
-          path: fhirpath_string,
-          name: identifier,
-          collection: bool,
-          description: string,
-          type: string,
-          tag: $ref('tag')
+    $defs: {
+      tag: {
+        type: array,
+        items: {
+          type: object,
+          additionalProperties: false,
+          properties: {
+            name: string,
+            value: string
+          }
         }
-      }
-    },
-    select: {
-      type: array,
-      minItems: 1,
-      items: {
-        type: object,
-        additionalProperties: false,
-        properties: {
-          column: $ref('column'),
-          unionAll: $ref('select'),
-          forEach: fhirpath_string,
-          forEachOrNull: fhirpath_string,
-          select: $ref('select')
+      },
+      column: {
+        type: array,
+        minItems: 1,
+        items: {
+          type: object,
+          required: column_required_fields,
+          additionalProperties: false,
+          properties: {
+            path: fhirpath_string,
+            name: identifier,
+            collection: bool,
+            description: string,
+            type: string,
+            tag: $ref('tag')
+          }
+        }
+      },
+      select: {
+        type: array,
+        minItems: 1,
+        items: {
+          type: object,
+          additionalProperties: false,
+          properties: {
+            column: $ref('column'),
+            unionAll: $ref('select'),
+            forEach: fhirpath_string,
+            forEachOrNull: fhirpath_string,
+            select: $ref('select')
+          }
         }
       }
     }
   }
-};
+
+  return schema
+}
+
 
 const ajv = new Ajv({ allErrors: true })
 function validate_fhirpath(path) {
@@ -135,8 +152,16 @@ function validate_fhirpath(path) {
 }
 ajv.addFormat('fhirpath-expression',{type: 'string', validate:  validate_fhirpath})
 
-export function validate(viewdef) {
-  const validate_schema = ajv.compile(viewdef_schema);
+let schema_test = viewdef_schema(true);
+let schema_playground = viewdef_schema(false);
+
+export function validate(viewdef, for_tests = true) {
+  let validate_schema
+  if (for_tests) {
+    validate_schema = ajv.compile(schema_test);
+  } else {
+    validate_schema = ajv.compile(schema_playground);
+  }
   validate_schema(viewdef);
   return validate_schema;
 }
diff --git a/test_report/src/Playground.svelte b/test_report/src/Playground.svelte
index d65ad34..dba3f33 100644
--- a/test_report/src/Playground.svelte
+++ b/test_report/src/Playground.svelte
@@ -117,7 +117,7 @@
      try {
          error = null;
          eval('v = ' + viewdef)
-         result = tabelize(v, evaluate(v, data));
+         result = tabelize(v, evaluate(v, data, false));
          /* tabelize(result) */
      } catch(e) {
          error = e.toString();