Add needs job output (#629)

* Add outputs field to job model

* Add output interpolation for jobs

* Add otto config reference for interpolated job output values into 'needs' context

* Add output interpolation call after job has completed.

* gofmt

* Remove whitespace

* goimports

Co-authored-by: Casey Lee <cplee@nektos.com>

act/model/workflow_test.go

@@ -131,6 +131,48 @@ jobs:
 	assert.Equal(t, workflow.Jobs["test"].Steps[4].Type(), StepTypeUsesActionLocal)
 }
 
+// See: https://docs.github.com/en/actions/reference/workflow-syntax-for-github-actions#jobsjob_idoutputs
+func TestReadWorkflow_JobOutputs(t *testing.T) {
+	yaml := `
+name: job outputs definition
+
+jobs:
+  test1:
+    runs-on: ubuntu-latest
+    steps:
+      - id: test1_1
+        run: |
+          echo "::set-output name=a_key::some-a_value"
+          echo "::set-output name=b-key::some-b-value"
+    outputs:
+      some_a_key: ${{ steps.test1_1.outputs.a_key }}
+      some-b-key: ${{ steps.test1_1.outputs.b-key }}
+
+  test2:
+    runs-on: ubuntu-latest
+    needs:
+      - test1
+    steps:
+      - name: test2_1
+        run: |
+          echo "${{ needs.test1.outputs.some_a_key }}"
+          echo "${{ needs.test1.outputs.some-b-key }}"
+`
+
+	workflow, err := ReadWorkflow(strings.NewReader(yaml))
+	assert.NoError(t, err, "read workflow should succeed")
+	assert.Len(t, workflow.Jobs, 2)
+
+	assert.Len(t, workflow.Jobs["test1"].Steps, 1)
+	assert.Equal(t, StepTypeRun, workflow.Jobs["test1"].Steps[0].Type())
+	assert.Equal(t, "test1_1", workflow.Jobs["test1"].Steps[0].ID)
+	assert.Len(t, workflow.Jobs["test1"].Outputs, 2)
+	assert.Contains(t, workflow.Jobs["test1"].Outputs, "some_a_key")
+	assert.Contains(t, workflow.Jobs["test1"].Outputs, "some-b-key")
+	assert.Equal(t, "${{ steps.test1_1.outputs.a_key }}", workflow.Jobs["test1"].Outputs["some_a_key"])
+	assert.Equal(t, "${{ steps.test1_1.outputs.b-key }}", workflow.Jobs["test1"].Outputs["some-b-key"])
+}
+
 func TestStep_ShellCommand(t *testing.T) {
 	tests := []struct {
 		shell string