Implement the compileable source code of the basic integration test suite.

This is the first step in moving the integration test suite to a more
reliable Golang based one.

postgres_exporter_integration_test.go

@@ -0,0 +1,60 @@
+// These are specialized integration tests. We only build them when we're doing
+// a lot of additional work to keep the external docker environment they require
+// working.
+// +build integration
+
+package main
+
+import (
+	"os"
+	"testing"
+
+	. "gopkg.in/check.v1"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"database/sql"
+	_ "github.com/lib/pq"
+)
+
+// Hook up gocheck into the "go test" runner.
+func Test(t *testing.T) { TestingT(t) }
+
+type IntegrationSuite struct{
+	e *Exporter
+}
+
+var _ = Suite(&IntegrationSuite{})
+
+func (s *IntegrationSuite) SetUpSuite(c *C) {
+	dsn := os.Getenv("DATA_SOURCE_NAME")
+	c.Assert(dsn, Not(Equals), "")
+
+	exporter := NewExporter(dsn)
+	c.Assert(exporter, NotNil)
+	// Assign the exporter to the suite
+	s.e = exporter
+
+	prometheus.MustRegister(exporter)
+}
+
+func (s *IntegrationSuite) TestAllNamespacesReturnResults(c *C) {
+	// Setup a dummy channel to consume metrics
+	ch := make(chan prometheus.Metric, 100)
+	go func() {
+		for _ = range ch {}
+	}()
+
+	// Open a database connection
+	db, err := sql.Open("postgres", s.e.dsn)
+	c.Assert(db, NotNil)
+	c.Assert(err, IsNil)
+	defer db.Close()
+
+	// Check the show variables work
+	nonFatalErrors := queryShowVariables(ch, db, s.e.variableMap)
+	c.Check(len(nonFatalErrors), Equals, 0)
+
+	// This should never happen in our test cases.
+	errMap := queryNamespaceMappings(ch, db, s.e.metricMap)
+	c.Check(len(errMap), Equals, 0)
+}