Strip extra trailing newlines in templates

When wrapping table format in range, string extra new lines from table
ends.

Fixes https://bugzilla.redhat.com/show_bug.cgi?id=1855983

Signed-off-by: Jhon Honce <jhonce@redhat.com>

common/pkg/report/template.go

@@ -130,7 +130,7 @@ func NewTemplate(name string) *Template {
 func (t *Template) Parse(text string) (*Template, error) {
 	if strings.HasPrefix(text, "table ") {
 		t.isTable = true
-		text = "{{range .}}" + NormalizeFormat(text) + "{{end}}"
+		text = "{{range .}}" + NormalizeFormat(text) + "{{end -}}"
 	} else {
 		text = NormalizeFormat(text)
 	}
@@ -157,12 +157,12 @@ func (t *Template) IsTable() bool {
 	return t.isTable
 }
 
-var rangeRegex = regexp.MustCompile(`{{\s*range\s*\.\s*}}.*{{\s*end\s*}}`)
+var rangeRegex = regexp.MustCompile(`{{\s*range\s*\.\s*}}.*{{\s*end\s*-?\s*}}`)
 
 // EnforceRange ensures that the format string contains a range
 func EnforceRange(format string) string {
 	if !rangeRegex.MatchString(format) {
-		return "{{range .}}" + format + "{{end}}"
+		return "{{range .}}" + format + "{{end -}}"
 	}
 	return format
 }

common/pkg/report/template_test.go

@@ -158,8 +158,43 @@ func TestTemplate_HasTable(t *testing.T) {
 }
 
 func TestTemplate_EnforceRange(t *testing.T) {
-	testRange := `{{range .}}foobar was here{{end}}`
+	testRange := `{{range .}}foobar was here{{end -}}`
 	assert.Equal(t, testRange, EnforceRange(testRange))
 	assert.Equal(t, testRange, EnforceRange("foobar was here"))
 	assert.NotEqual(t, testRange, EnforceRange("foobar"))
+
+	// Do not override a given range
+	testRange = `{{range .}}foobar was here{{end}}`
+	assert.Equal(t, testRange, EnforceRange(testRange))
+}
+
+func TestTemplate_Newlines(t *testing.T) {
+	input := []struct {
+		Field1 string
+		Field2 int
+		Field3 string
+	}{
+		{Field1: "One", Field2: 1, Field3: "First"},
+		{Field1: "Two", Field2: 2, Field3: "Second"},
+		{Field1: "Three", Field2: 3, Field3: "Third"},
+	}
+
+	hdrs := Headers(input[0], map[string]string{"Field1": "Ein", "Field2": "Zwei", "Field3": "Drei"})
+
+	// Ensure no blank lines in table
+	expected := "EIN\tZWEI\tDREI\nOne\t1\tFirst\nTwo\t2\tSecond\nThree\t3\tThird\n"
+
+	format := NormalizeFormat("{{.Field1}}\t{{.Field2}}\t{{.Field3}}")
+	format = EnforceRange(format)
+	tmpl, err := NewTemplate("TestTemplate").Parse(format)
+	assert.NoError(t, err)
+
+	var buf bytes.Buffer
+	err = tmpl.Execute(&buf, hdrs)
+	assert.NoError(t, err)
+
+	err = tmpl.Execute(&buf, input)
+	assert.NoError(t, err)
+
+	assert.Equal(t, expected, buf.String())
 }