travis, build, consensus: drop support for Go 1.7

consensus/ethash/algorithm_test.go

@@ -30,6 +30,22 @@ import (
 	"github.com/ethereum/go-ethereum/core/types"
 )
 
+// Tests whether the dataset size calculator works correctly by cross checking the
+// hard coded lookup table with the value generated by it.
+func TestSizeCalculations(t *testing.T) {
+	// Verify all the cache and dataset sizes from the lookup table.
+	for epoch, want := range cacheSizes {
+		if size := calcCacheSize(epoch); size != want {
+			t.Errorf("cache %d: cache size mismatch: have %d, want %d", epoch, size, want)
+		}
+	}
+	for epoch, want := range datasetSizes {
+		if size := calcDatasetSize(epoch); size != want {
+			t.Errorf("dataset %d: dataset size mismatch: have %d, want %d", epoch, size, want)
+		}
+	}
+}
+
 // Tests that verification caches can be correctly generated.
 func TestCacheGeneration(t *testing.T) {
 	tests := []struct {