Fix missing newline between metrics when collecting #15 (#16)

* Fix missing newline between metrics when collecting

Resolves #15

* Newline for CI

* Newline for CI

Author: ktoso

.gitignore

@@ -3,4 +3,5 @@
 /Packages
 /*.xcodeproj
 build/
-.swiftpm/
+.swiftpm/
+.idea

Package.resolved

@@ -52,6 +52,7 @@ public class PrometheusClient {
             var buffer = ByteBufferAllocator().buffer(capacity: 0)
             self.metrics.forEach {
                 $0.collect(into: &buffer)
+                buffer.writeString("\n")
             }
             succeed(buffer)
         }

Sources/Prometheus/Prometheus.swift

@@ -156,7 +156,7 @@ final class PrometheusMetricsTests: XCTestCase {
         XCTAssertEqual(try! promise.futureResult.wait(), "")
     }
 
-    func testBuffer() {
+    func testCollectIntoBuffer() {
         let counter = Counter(label: "my_counter")
         counter.increment(by: 10)
         let counterTwo = Counter(label: "my_counter", dimensions: [("myValue", "labels")])
@@ -169,8 +169,52 @@ final class PrometheusMetricsTests: XCTestCase {
         XCTAssertEqual(buffer.readString(length: buffer.readableBytes), """
         # TYPE my_counter counter
         my_counter 10
-        my_counter{myValue=\"labels\"} 10
+        my_counter{myValue=\"labels\"} 10\n
         """)
     }
+
+    func testCollectAFewMetricsIntoBuffer() {
+        let counter = Counter(label: "my_counter")
+        counter.increment(by: 10)
+        let counterA = Counter(label: "my_counter", dimensions: [("a", "aaa"), ("x", "x")])
+        counterA.increment(by: 4)
+        let gauge = Gauge(label: "my_gauge")
+        gauge.record(100)
+
+        let promise = self.eventLoop.makePromise(of: ByteBuffer.self)
+        prom.collect(promise.succeed)
+        var buffer = try! promise.futureResult.wait()
+
+        XCTAssertEqual(buffer.readString(length: buffer.readableBytes),
+            """
+            # TYPE my_counter counter
+            my_counter 10
+            my_counter{x="x", a="aaa"} 4
+            # TYPE my_gauge gauge
+            my_gauge 100.0\n
+            """)
+    }
+
+    func testCollectAFewMetricsIntoString() {
+        let counter = Counter(label: "my_counter")
+        counter.increment(by: 10)
+        let counterA = Counter(label: "my_counter", dimensions: [("a", "aaa"), ("x", "x")])
+        counterA.increment(by: 4)
+        let gauge = Gauge(label: "my_gauge")
+        gauge.record(100)
+
+        let promise = self.eventLoop.makePromise(of: String.self)
+        prom.collect(promise.succeed)
+        let string = try! promise.futureResult.wait()
+
+        XCTAssertEqual(string,
+            """
+            # TYPE my_counter counter
+            my_counter 10
+            my_counter{x="x", a="aaa"} 4
+            # TYPE my_gauge gauge
+            my_gauge 100.0
+            """)
+    }
 }
 

Tests/SwiftPrometheusTests/PrometheusMetricsTests.swift

@@ -6,6 +6,9 @@ extension PrometheusMetricsTests {
     //   `swift test --generate-linuxmain`
     // to regenerate.
     static let __allTests__PrometheusMetricsTests = [
+        ("testCollectAFewMetricsIntoBuffer", testCollectAFewMetricsIntoBuffer),
+        ("testCollectAFewMetricsIntoString", testCollectAFewMetricsIntoString),
+        ("testCollectIntoBuffer", testCollectIntoBuffer),
         ("testCounter", testCounter),
         ("testGauge", testGauge),
         ("testHistogram", testHistogram),