diff --git a/public/app/plugins/datasource/prometheus/specs/completer_specs.ts b/public/app/plugins/datasource/prometheus/specs/completer_specs.ts
index 903ce0b5d3b..3d0371da7ed 100644
--- a/public/app/plugins/datasource/prometheus/specs/completer_specs.ts
+++ b/public/app/plugins/datasource/prometheus/specs/completer_specs.ts
@@ -5,23 +5,110 @@ import {PrometheusDatasource} from '../datasource';
 
 describe('Prometheus editor completer', function() {
 
-  let editor = {};
-  let session = {
-    getTokenAt: sinon.stub().returns({}),
-    getLine:  sinon.stub().returns(""),
+  let sessionData = {
+    currentToken: {},
+    tokens: [],
+    line: ''
   };
+  let session = {
+    getTokenAt: sinon.stub().returns(sessionData.currentToken),
+    getTokens: sinon.stub().returns(sessionData.tokens),
+    getLine: sinon.stub().returns(sessionData.line),
+  };
+  let editor = { session: session };
 
-  let datasourceStub = <PrometheusDatasource>{};
+  let datasourceStub = <PrometheusDatasource>{
+    performInstantQuery: sinon.stub().returns(Promise.resolve(
+      [
+        {
+          metric: {
+            job: 'node',
+            instance: 'localhost:9100'
+          }
+        }
+      ]
+    )),
+    performSuggestQuery: sinon.stub().returns(Promise.resolve(
+      [
+        'node_cpu'
+      ]
+    ))
+  };
   let completer = new PromCompleter(datasourceStub);
 
   describe("When inside brackets", () => {
 
     it("Should return range vectors", () => {
-      completer.getCompletions(editor, session, 10, "[", (s, res) => {
+      completer.getCompletions(editor, session, { row: 0, column: 10 }, '[', (s, res) => {
         expect(res[0]).to.eql({caption: '1s', value: '[1s', meta: 'range vector'});
       });
     });
 
   });
 
+  describe("When inside label matcher, and located at label name", () => {
+    sessionData = {
+      currentToken: { type: 'entity.name.tag', value: 'j', index: 2, start: 9 },
+      tokens: [
+        { type: 'identifier', value: 'node_cpu' },
+        { type: 'paren.lparen', value: '{' },
+        { type: 'entity.name.tag', value: 'j', index: 2, start: 9 },
+        { type: 'paren.rparen', value: '}' }
+      ],
+      line: 'node_cpu{j}'
+    };
+
+    it("Should return label name list", () => {
+      completer.getCompletions(editor, session, { row: 0, column: 10 }, 'j', (s, res) => {
+        expect(res[0]).to.eql({caption: 'job', value: 'job', meta: 'label name'});
+      });
+    });
+
+  });
+
+  describe("When inside label matcher, and located at label name with __name__ match", () => {
+    sessionData = {
+      currentToken: { type: 'entity.name.tag', value: 'j', index: 5, start: 22 },
+      tokens: [
+        { type: 'paren.lparen', value: '{' },
+        { type: 'entity.name.tag', value: '__name__' },
+        { type: 'keyword.operator', value: '=~' },
+        { type: 'string.quoted', value: '"node_cpu"' },
+        { type: 'punctuation.operator', value: ',' },
+        { type: 'entity.name.tag', value: 'j', 'index': 5, 'start': 22 },
+        { type: 'paren.rparen', value: '}' }
+      ],
+      line: '{__name__=~"node_cpu",j}'
+    };
+
+    it("Should return label name list", () => {
+      completer.getCompletions(editor, session, { row: 0, column: 23 }, 'j', (s, res) => {
+        expect(res[0]).to.eql({caption: 'job', value: 'job', meta: 'label name'});
+      });
+    });
+
+  });
+
+  describe("When inside label matcher, and located at label value", () => {
+    sessionData = {
+      currentToken: { type: 'string.quoted', value: '"n"', index: 4, start: 13 },
+      tokens: [
+        { type: 'identifier', value: 'node_cpu' },
+        { type: 'paren.lparen', value: '{' },
+        { type: 'entity.name.tag', value: 'job' },
+        { type: 'keyword.operator', value: '=' },
+        { type: 'string.quoted', value: '"n"', index: 4, start: 13 },
+        { type: 'paren.rparen', value: '}' }
+      ],
+      line: 'node_cpu{job="n"}'
+    };
+
+    it("Should return label value list", () => {
+      completer.getCompletions(editor, session, { row: 0, column: 15 }, 'n', (s, res) => {
+        expect(res[0]).to.eql({caption: 'node', value: 'node', meta: 'label value'});
+      });
+    });
+
+  });
+
 });