more testing

line.go

@@ -45,7 +45,9 @@ func (l *LineWriter) WriteEvent(e *Event) {
 	}
 
 	buf.WriteRune('[')
+	if e.Path != nil {
 		buf.WriteString(e.Path.String())
+	}
 	buf.WriteRune(']')
 	buf.WriteRune(' ')
 
@@ -54,10 +56,13 @@ func (l *LineWriter) WriteEvent(e *Event) {
 	} else {
 		buf.WriteRune('[')
 		writeTags(buf, e.Tags)
-		buf.WriteString("] ")
+		buf.WriteRune(']')
 	}
 
+	if e.Text != "" {
+		buf.WriteRune(' ')
 		buf.WriteString(strings.ReplaceAll(e.Text, string('\n'), "\n"))
+	}
 
 	l.out.Lock()
 	l.out.Write(buf.Bytes())

line_test.go

@@ -7,20 +7,129 @@ import (
 )
 
 func TestLineWriter(t *testing.T) {
-	var buf bytes.Buffer
-	w := NewLineWriter(&buf)
-	w.WriteEvent(&Event{
-		Level: Debug,
-		Time:  time.Now(),
-		Path:  NewPath("alice").Child("bob").Child("carol"),
-		Text:  "hey you farthead",
+	refTime := time.Date(2020, time.January, 13, 12, 26, 47, 999999, time.UTC)
+
+	tests := []struct {
+		name  string
+		event Event
+		line  string
+	}{
+		{
+			name:  "empty event",
+			event: Event{},
+			line:  `0001-01-01T00:00:00Z d [] []`,
+		},
+		{
+			name: "just a time",
+			event: Event{
+				Time: refTime,
+			},
+			line: `2020-01-13T12:26:47Z d [] []`,
+		},
+		{
+			name: "root path only",
+			event: Event{
+				Time: refTime,
+				Path: NewPath("root"),
+			},
+			line: `2020-01-13T12:26:47Z d [root] []`,
+		},
+		{
+			name: "child path",
+			event: Event{
+				Time: refTime,
+				Path: NewPath("root").Child("kid"),
+			},
+			line: `2020-01-13T12:26:47Z d [root/kid] []`,
+		},
+		{
+			name: "another child path",
+			event: Event{
+				Time: refTime,
+				Path: NewPath("root").Child("kid").Child("fart"),
+			},
+			line: `2020-01-13T12:26:47Z d [root/kid/fart] []`,
+		},
+		{
+			name: "a message",
+			event: Event{
+				Time: refTime,
+				Path: NewPath("root").Child("kid").Child("fart"),
+				Text: "this is a message",
+			},
+			line: `2020-01-13T12:26:47Z d [root/kid/fart] [] this is a message`,
+		},
+		{
+			name: "a message with an empty tag",
+			event: Event{
+				Time: refTime,
+				Path: NewPath("root").Child("kid").Child("fart"),
+				Text: "this is a message",
+				Tags: &Tags{key: "alert"},
+			},
+			line: `2020-01-13T12:26:47Z d [root/kid/fart] [alert] this is a message`,
+		},
+		{
+			name: "a message with two empty tags",
+			event: Event{
+				Time: refTime,
+				Path: NewPath("root").Child("kid").Child("fart"),
+				Text: "this is a message",
+				Tags: &Tags{
+					key:    "zombo-dot-com",
+					parent: &Tags{key: "alert"},
+				},
+			},
+			line: `2020-01-13T12:26:47Z d [root/kid/fart] [alert+zombo-dot-com] this is a message`,
+		},
+		{
+			name: "a message with an int tag",
+			event: Event{
+				Time: refTime,
+				Path: NewPath("root").Child("kid").Child("fart"),
+				Text: "this is a message",
 				Tags: &Tags{
-			key: "poop",
+					key:   "num-users",
+					value: 15,
+				},
+			},
+			line: `2020-01-13T12:26:47Z d [root/kid/fart] [num-users=15] this is a message`,
+		},
+		{
+			name: "a message with a variety of tags",
+			event: Event{
+				Time: refTime,
+				Path: NewPath("root").Child("kid").Child("fart"),
+				Text: "this is a message",
+				Tags: &Tags{
+					key:   "num-users",
+					value: 15,
 					parent: &Tags{
-				key:   "num_poops",
-				value: 27,
+						key:   "pi",
+						value: 3.14,
+						parent: &Tags{
+							key:   "request-id",
+							value: "b49d31c7-d3bb-4bd3-96fe-34e7c7d2b0a4",
+						},
 					},
 				},
+			},
+			line: `2020-01-13T12:26:47Z d [root/kid/fart] [request-id=b49d31c7-d3bb-4bd3-96fe-34e7c7d2b0a4+pi=3.14+num-users=15] this is a message`,
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			var buf bytes.Buffer
+			w := NewLineWriter(&buf)
+			w.WriteEvent(&test.event)
+			line := buf.String()
+			if line != test.line {
+				t.Log("expected line does not match observed line")
+				t.Logf("expected line: '%s'", test.line)
+				t.Logf("observed line: '%s'", line)
+				t.Fail()
+			}
 		})
-	t.Error(buf.String())
+	}
 }

tag.go

@@ -1,23 +1,39 @@
 package blammo
 
+// Tags represent event metadata. Tags is an ordered collection of key-value
+// pairs where every key is a string. Values are optional, and may be one of
+// int, float64, and string. The same key may appear multiple times.
+//
+// Tags is internally represented by a singly linked list of key-value pairs. A
+// Tags struct is immutable once created. The only thing that can be done is to
+// create new nodes that point to old nodes. This allows us to continually
+// recycle tag nodes that are widely used across an application.
 type Tags struct {
 	key    string
 	value  interface{}
 	parent *Tags
 }
 
+// Tag creates a new Tags struct having the given key as its final key, with no
+// associated value. All existing keys continue to exist.
 func (t *Tags) Tag(key string) *Tags {
 	return &Tags{key: key, parent: t}
 }
 
+// TagInt creates a new Tags struct having the given key-value pair as the
+// final key-value pair. All existing key-value pairs continue to exist.
 func (t *Tags) TagInt(key string, v int) *Tags {
 	return &Tags{key: key, value: v, parent: t}
 }
 
+// TagString creates a new Tags struct having the given key-value pair as the
+// final key-value pair. All existing key-value pairs continue to exist.
 func (t *Tags) TagString(key, v string) *Tags {
 	return &Tags{key: key, value: v, parent: t}
 }
 
+// TagFloat creates a new Tags struct having the given key-value pair as the
+// final key-value pair. All existing key-value pairs continue to exist.
 func (t *Tags) TagFloat(key string, v float64) *Tags {
 	return &Tags{key: key, value: v, parent: t}
 }