tflog+tfsdklog: Add root and subsystem unit testing (#33)

Reference: #31

Backfill unit testing for the following functions:

- `With()` / `SubsystemWith()`
- `Trace()`/ `SubsystemTrace()`
- `Debug()`/ `SubsystemDebug()`
- `Info()`/ `SubsystemInfo()`
- `Warn()`/ `SubsystemWarn()`
- `Error()`/ `SubsystemError()`

Author: bflad

.golangci.yml

@@ -14,7 +14,7 @@ linters:
     - ineffassign
     - makezero
     - nilerr
-    - paralleltest
+    # - paralleltest # Reference: https://github.com/kunwardeep/paralleltest/issues/14
     - predeclared
     - staticcheck
     # - tenv # TODO: Enable when upgrading Go 1.16 to 1.17

go.mod

@@ -3,6 +3,7 @@ module github.com/hashicorp/terraform-plugin-log
 go 1.16
 
 require (
+	github.com/google/go-cmp v0.5.7
 	github.com/hashicorp/go-hclog v1.1.0
 	github.com/mitchellh/go-testing-interface v1.14.1
 	github.com/stretchr/testify v1.3.0 // indirect

go.sum

@@ -3,6 +3,8 @@ github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/fatih/color v1.7.0 h1:DkWD4oS2D8LGGgTQ6IvwJJXSL5Vp2ffcQg58nFV38Ys=
 github.com/fatih/color v1.7.0/go.mod h1:Zm6kSWBoL9eyXnKyktHP6abPY2pDugNf5KwzbycvMj4=
+github.com/google/go-cmp v0.5.7 h1:81/ik6ipDQS2aGcBfIN5dHDB36BwrStyeAQquSYCV4o=
+github.com/google/go-cmp v0.5.7/go.mod h1:n+brtR0CgQNWTVd5ZUFpTBC8YFBDLK/h/bpaJ8/DtOE=
 github.com/hashicorp/go-hclog v1.1.0 h1:QsGcniKx5/LuX2eYoeL+Np3UKYPNaN7YKpTh29h8rbw=
 github.com/hashicorp/go-hclog v1.1.0/go.mod h1:whpDNt7SSdeAju8AWKIWsul05p54N/39EeqMAyrmvFQ=
 github.com/mattn/go-colorable v0.1.4 h1:snbPLB8fVfU9iwbbo30TPtbLRzwWu6aJS6Xh4eaaviA=
@@ -21,3 +23,5 @@ github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UV
 golang.org/x/sys v0.0.0-20190222072716-a9d3bda3a223/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20191008105621-543471e840be h1:QAcqgptGM8IQBC9K/RC4o+O9YmqEm0diQn9QmZw/0mU=
 golang.org/x/sys v0.0.0-20191008105621-543471e840be/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 h1:E7g+9GITq07hpfrRu66IVDexMakfv52eLZ2CXBWiKr4=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=

internal/loggertest/json_decode.go

@@ -0,0 +1,30 @@
+package loggertest
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+)
+
+func MultilineJSONDecode(data io.Reader) ([]map[string]interface{}, error) {
+	var result []map[string]interface{}
+	var entry map[string]interface{}
+
+	dec := json.NewDecoder(data)
+
+	for {
+		err := dec.Decode(&entry)
+
+		if err == io.EOF {
+			break
+		}
+
+		if err != nil {
+			return result, fmt.Errorf("unable to decode JSON: %s", err)
+		}
+
+		result = append(result, entry)
+	}
+
+	return result, nil
+}

internal/loggertest/provider.go

@@ -0,0 +1,22 @@
+package loggertest
+
+import (
+	"context"
+	"io"
+
+	"github.com/hashicorp/go-hclog"
+	"github.com/hashicorp/terraform-plugin-log/internal/logging"
+)
+
+func ProviderRoot(ctx context.Context, output io.Writer) context.Context {
+	loggerOptions := &hclog.LoggerOptions{
+		DisableTime: true,
+		JSONFormat:  true,
+		Level:       hclog.Trace,
+		Output:      output,
+	}
+
+	ctx = logging.SetProviderRootLogger(ctx, hclog.New(loggerOptions))
+
+	return ctx
+}

internal/loggertest/sdk.go

@@ -0,0 +1,22 @@
+package loggertest
+
+import (
+	"context"
+	"io"
+
+	"github.com/hashicorp/go-hclog"
+	"github.com/hashicorp/terraform-plugin-log/internal/logging"
+)
+
+func SDKRoot(ctx context.Context, output io.Writer) context.Context {
+	loggerOptions := &hclog.LoggerOptions{
+		DisableTime: true,
+		JSONFormat:  true,
+		Level:       hclog.Trace,
+		Output:      output,
+	}
+
+	ctx = logging.SetSDKRootLogger(ctx, hclog.New(loggerOptions))
+
+	return ctx
+}