Merge pull request #60 from gruntwork-io/test-data

Add ability to test whether test data exists.

_docker-images/gruntwork-amzn-linux-test/Dockerfile

@@ -11,4 +11,15 @@ RUN yum update -y && \
         sudo \
         vim \
         wget && \
-        yum clean all
+        yum clean all
+
+# Installing pip with yum doesn't actually put it in the PATH, so we use easy_install instead. Pip will now be placed
+# in /usr/local/bin, but amazonlinux's sudo uses a sanitzed PATH that does not include /usr/local/bin, so we symlink pip.
+RUN curl https://bootstrap.pypa.io/ez_setup.py | sudo /usr/bin/python && \
+    easy_install pip && \
+    pip install --upgrade pip && \
+    ln -s /usr/local/bin/pip /usr/bin/pip
+
+# Install the AWSCLI (which apparently does not come pre-bundled with Amazon Linux!)
+RUN pip install --upgrade setuptools && \
+    pip install awscli --upgrade

test-structure/test_structure.go

@@ -154,6 +154,72 @@ func LoadTestData(t *testing.T, path string, value interface{}, logger *log.Logg
 	}
 }
 
+// Return true if a file exists at $path and the test data there is non-empty.
+func IsTestDataPresent(t *testing.T, path string, logger *log.Logger) bool {
+	logger.Printf("Testing whether test data exists at %s", path)
+
+	bytes, err := ioutil.ReadFile(path)
+	if err != nil && strings.Contains(err.Error(), "no such file or directory") {
+		logger.Printf("No test data was found at %s", path)
+		return false
+	} else if err != nil {
+		t.Fatalf("Failed to load test data from %s due to unexpected error: %v", path, err)
+	}
+
+	if isEmptyJson(t, bytes) {
+		logger.Printf("No test data was found at %s", path)
+		return false
+	}
+
+	logger.Printf("Non-empty test data found at %s", path)
+	return true
+}
+
+// Return true if the given bytes are empty, or in a valid JSON format that can reasonably be considered empty.
+// The types used are based on the type possibilities listed at https://golang.org/src/encoding/json/decode.go?s=4062:4110#L51
+func isEmptyJson(t *testing.T, bytes []byte) bool {
+	var value interface{}
+
+	if len(bytes) == 0 {
+		return true
+	}
+
+	if err := json.Unmarshal(bytes, &value); err != nil {
+		t.Fatalf("Failed to parse JSON while testing whether it is empty: %v", err)
+	}
+
+	if value == nil {
+		return true
+	}
+
+	valueBool, ok := value.(bool)
+	if ok && ! valueBool {
+		return true
+	}
+
+	valueFloat64, ok := value.(float64)
+	if ok && valueFloat64 == 0 {
+		return true
+	}
+
+	valueString, ok := value.(string)
+	if ok && valueString == "" {
+		return true
+	}
+
+	valueSlice, ok := value.([]interface{})
+	if ok && len(valueSlice) == 0 {
+		return true
+	}
+
+	valueMap, ok := value.(map[string]interface{})
+	if ok && len(valueMap) == 0 {
+		return true
+	}
+
+	return false
+}
+
 // Clean up the test data at the given path
 func CleanupTestData(t *testing.T, path string, logger *log.Logger) {
 	if files.FileExists(path) {

test-structure/test_structure_test.go

@@ -20,6 +20,9 @@ func TestSaveAndLoadTestData(t *testing.T) {
 
 	logger := terralog.NewLogger("TestSaveAndLoadTestData")
 
+	isTestDataPresent := IsTestDataPresent(t, "/file/that/does/not/exist", logger)
+	assert.False(t, isTestDataPresent, "Expected no test data would be present because no test data file exists.")
+
 	tmpFile, err := ioutil.TempFile("", "save-and-load-test-data")
 	if err != nil {
 		t.Fatalf("Failed to create temp dir: %v", err)
@@ -30,8 +33,15 @@ func TestSaveAndLoadTestData(t *testing.T) {
 		Bar: true,
 		Baz: map[string]interface{}{"abc": "def", "ghi": 1.0, "klm": false},
 	}
+
+	isTestDataPresent = IsTestDataPresent(t, tmpFile.Name(), logger)
+	assert.False(t, isTestDataPresent, "Expected no test data would be present because file exists but no data has been written yet.")
+
 	SaveTestData(t, tmpFile.Name(), expectedData, logger)
 
+	isTestDataPresent = IsTestDataPresent(t, tmpFile.Name(), logger)
+	assert.True(t, isTestDataPresent, "Expected test data would be present because file exists and data has been written to file.")
+
 	actualData := testData{}
 	LoadTestData(t, tmpFile.Name(), &actualData, logger)
 	assert.Equal(t, expectedData, actualData)
@@ -40,6 +50,49 @@ func TestSaveAndLoadTestData(t *testing.T) {
 	assert.False(t, files.FileExists(tmpFile.Name()))
 }
 
+func TestIsEmptyJson(t *testing.T) {
+	t.Parallel()
+
+	var jsonValue []byte
+	var isEmpty bool
+
+	jsonValue = []byte("null")
+	isEmpty = isEmptyJson(t, jsonValue)
+	assert.True(t, isEmpty, `The JSON literal "null" should be treated as an empty value.`)
+
+	jsonValue = []byte("false")
+	isEmpty = isEmptyJson(t, jsonValue)
+	assert.True(t, isEmpty, `The JSON literal "false" should be treated as an empty value.`)
+
+	jsonValue = []byte("true")
+	isEmpty = isEmptyJson(t, jsonValue)
+	assert.False(t, isEmpty, `The JSON literal "true" should be treated as a non-empty value.`)
+
+	jsonValue = []byte("0")
+	isEmpty = isEmptyJson(t, jsonValue)
+	assert.True(t, isEmpty, `The JSON literal "0" should be treated as an empty value.`)
+
+	jsonValue = []byte("1")
+	isEmpty = isEmptyJson(t, jsonValue)
+	assert.False(t, isEmpty, `The JSON literal "1" should be treated as a non-empty value.`)
+
+	jsonValue = []byte("{}")
+	isEmpty = isEmptyJson(t, jsonValue)
+	assert.True(t, isEmpty, `The JSON value "{}" should be treated as an empty value.`)
+
+	jsonValue = []byte(`{ "key": "val" }`)
+	isEmpty = isEmptyJson(t, jsonValue)
+	assert.False(t, isEmpty, `The JSON value { "key": "val" } should be treated as a non-empty value.`)
+
+	jsonValue = []byte(`[]`)
+	isEmpty = isEmptyJson(t, jsonValue)
+	assert.True(t, isEmpty, `The JSON value "[]" should be treated as an empty value.`)
+
+	jsonValue = []byte(`[{ "key": "val" }]`)
+	isEmpty = isEmptyJson(t, jsonValue)
+	assert.False(t, isEmpty, `The JSON value [{ "key": "val" }] should be treated as a non-empty value.`)
+}
+
 func TestSaveAndLoadTerratestOptions(t *testing.T) {
 	t.Parallel()