Detect errors on missing schema refs

src/validators/json-schema.coffee

@@ -171,12 +171,23 @@ class JsonSchema
   #@private
   validateSchemaV4: =>
     result = tv4.validateMultiple @data, @schema
+    validationErrors = result.errors.concat result.missing
 
     amandaCompatibleError =
-      length: result.errors.length
+      length: validationErrors.length
       errorMessages: {}
 
-    for error, index in result?.errors
+    for err, index in validationErrors
+      # Need to create the error in case of missing schema errors.
+      # If tv4 meets $ref to a missing schema, it provides an array that contains the schema's domain.
+      # In case we a local $ref, as there's no domain name, it will look like this: ['', '': '']
+      if err instanceof Error
+        error = err
+      else
+        error = new Error('Missing schema')
+        error.params = { key: err }
+        error.dataPath = ''
+
       pathArray = jsonPointer.parse error.dataPath
       if error.params.key
         pathArray.push error.params.key

test/fixtures/invalid-schema-v4-with-refs.json

@@ -0,0 +1,16 @@
+{
+  "$schema": "http://json-schema.org/draft-04/schema#",
+  "definitions": {
+    "bar": {
+      "type": "string"
+    }
+  },
+  "type": "object",
+  "required": ["foo"],
+  "additionalProperties": false,
+  "properties": {
+    "foo": {
+      "$ref": "#/definitions/baz"
+    }
+  }
+}

test/fixtures/valid-schema-v4-with-refs.json

@@ -0,0 +1,16 @@
+{
+  "$schema": "http://json-schema.org/draft-04/schema#",
+  "definitions": {
+    "bar": {
+      "type": "string"
+    }
+  },
+  "type": "object",
+  "required": ["foo"],
+  "additionalProperties": false,
+  "properties": {
+    "foo": {
+      "$ref": "#/definitions/bar"
+    }
+  }
+}

test/unit/validators/json-schema-test.coffee

@@ -281,7 +281,6 @@ describe 'validatePrivate()', () ->
     it 'should not valiate using tv4', () ->
       assert.notOk validator.validateSchemaV4.called
 
-
   describe 'when @jsonSchemaVersion is set to v4', () ->
     validator = null
 
@@ -307,6 +306,62 @@ describe 'validatePrivate()', () ->
     it 'should not validate using amanda', () ->
       assert.notOk validator.validateSchemaV3.called
 
+  describe 'when valid v4 $ref schema provided with valid data', () ->
+    fn = null
+    validator = null
+
+    before () ->
+      validSchema = require '../../fixtures/valid-schema-v4-with-refs'
+      real = JSON.parse '''
+      { "foo": "bar" }
+      '''
+      fn = () ->
+        validator = new JsonSchema real, validSchema
+        validator.validatePrivate()
+
+    it 'should not return a validation error', () ->
+      assert.lengthOf fn(), 0
+
+  describe 'when valid v4 $ref schema provided with invalid data', () ->
+    fn = null
+    validator = null
+
+    before () ->
+      validSchema = require '../../fixtures/valid-schema-v4-with-refs'
+      real = JSON.parse '''
+      { "foo": 1 }
+      '''
+      fn = () ->
+        validator = new JsonSchema real, validSchema
+        validator.validatePrivate()
+
+    it 'should return a validation error', () ->
+      assert.lengthOf fn(), 1
+
+    it 'should mention an invalid type error', () ->
+      e = fn()[0]
+      assert.include e.message, "Invalid type"
+
+  describe 'when invalid v4 $ref schema provided with valid data', () ->
+    fn = null
+    validator = null
+
+    before () ->
+      invalidSchema = require '../../fixtures/invalid-schema-v4-with-refs'
+      real = JSON.parse '''
+      { "foo": "bar" }
+      '''
+      fn = () ->
+        validator = new JsonSchema real, invalidSchema
+        validator.validatePrivate()
+
+    it 'should return a validation error', () ->
+      assert.lengthOf fn(), 1
+
+    it 'should mention a missing schema error', () ->
+      e = fn()[0]
+      assert.include e.message, "Missing schema"
+
   describe 'when @jsonSchemaVersion is null', () ->
     fn = null
     validator = null