Add integration test for history command and fix bug where history

would occasionally be returned in the incorrect order if sequential
layers had the same created time.

Docker-DCO-1.1-Signed-off-by: Bryan Murphy <bmurphy1976@gmail.com> (github: bmurphy1976)

integration-cli/build_tests/TestBuildHistory/Dockerfile

@@ -0,0 +1,28 @@
+FROM busybox
+
+RUN echo "A"
+RUN echo "B"
+RUN echo "C"
+RUN echo "D"
+RUN echo "E"
+RUN echo "F"
+RUN echo "G"
+RUN echo "H"
+RUN echo "I"
+RUN echo "J"
+RUN echo "K"
+RUN echo "L"
+RUN echo "M"
+RUN echo "N"
+RUN echo "O"
+RUN echo "P"
+RUN echo "Q"
+RUN echo "R"
+RUN echo "S"
+RUN echo "T"
+RUN echo "U"
+RUN echo "V"
+RUN echo "W"
+RUN echo "X"
+RUN echo "Y"
+RUN echo "Z"

integration-cli/docker_cli_history_test.go

@@ -0,0 +1,43 @@
+package main
+
+import (
+	"fmt"
+	"os/exec"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+// This is a heisen-test.  Because the created timestamp of images and the behavior of
+// sort is not predictable it doesn't always fail.
+func TestBuildHistory(t *testing.T) {
+	buildDirectory := filepath.Join(workingDirectory, "build_tests", "TestBuildHistory")
+	buildCmd := exec.Command(dockerBinary, "build", "-t", "testbuildhistory", ".")
+
+	buildCmd.Dir = buildDirectory
+	out, exitCode, err := runCommandWithOutput(buildCmd)
+	errorOut(err, t, fmt.Sprintf("build failed to complete: %v %v", out, err))
+	if err != nil || exitCode != 0 {
+		t.Fatal("failed to build the image")
+	}
+
+	out, exitCode, err = runCommandWithOutput(exec.Command(dockerBinary, "history", "testbuildhistory"))
+	errorOut(err, t, fmt.Sprintf("image history failed: %v %v", out, err))
+	if err != nil || exitCode != 0 {
+		t.Fatal("failed to get image history")
+	}
+
+	actual_values := strings.Split(out, "\n")[1:27]
+	expected_values := [26]string{"Z", "Y", "X", "W", "V", "U", "T", "S", "R", "Q", "P", "O", "N", "M", "L", "K", "J", "I", "H", "G", "F", "E", "D", "C", "B", "A"}
+
+	for i := 0; i < 26; i++ {
+		echo_value := fmt.Sprintf("echo \"%s\"", expected_values[i])
+		actual_value := actual_values[i]
+
+		if !strings.Contains(actual_value, echo_value) {
+			t.Fatalf("Expected layer \"%s\", but was: %s", expected_values[i], actual_value)
+		}
+	}
+
+	deleteImages("testbuildhistory")
+}

server/server.go

@@ -840,7 +840,6 @@ func (srv *Server) ImageHistory(job *engine.Job) engine.Status {
 		outs.Add(out)
 		return nil
 	})
-	outs.ReverseSort()
 	if _, err := outs.WriteListTo(job.Stdout); err != nil {
 		return job.Error(err)
 	}