add stack test

Author: savil

internal/impl/envpath/stack_test.go

@@ -0,0 +1,103 @@
+package envpath
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestNewStack(t *testing.T) {
+
+	// Initialize a new Stack from the existing env
+	env := map[string]string{
+		"PATH": "/init-path",
+	}
+	stack := Stack(env)
+	if len(stack.keys) == 0 {
+		t.Errorf("Stack has no keys but should have %s", InitPathEnv)
+	}
+	if len(stack.keys) != 1 {
+		t.Errorf("Stack has should have exactly one key (%s) but has %d keys. Keys are: %s",
+			InitPathEnv, len(stack.keys), strings.Join(stack.keys, ", "))
+	}
+
+	// Each testStep below is applied in order, and the resulting env
+	// is used implicitly as input into the subsequent test step.
+	//
+	// These test steps are NOT independent! These are not "test cases" that
+	// would usually be independent.
+	testSteps := []struct {
+		projectHash        string
+		nixEnvPath         string
+		preservePathStack  bool
+		expectedKeysLength int
+		expectedEnv        map[string]string
+	}{
+		{
+			projectHash:        "fooProjectHash",
+			nixEnvPath:         "/foo1:/foo2",
+			preservePathStack:  false,
+			expectedKeysLength: 2,
+			expectedEnv: map[string]string{
+				"PATH":                "/foo1:/foo2:/init-path",
+				InitPathEnv:           "/init-path",
+				Key("fooProjectHash"): "/foo1:/foo2",
+			},
+		},
+		{
+			projectHash:        "barProjectHash",
+			nixEnvPath:         "/bar1:/bar2",
+			preservePathStack:  false,
+			expectedKeysLength: 3,
+			expectedEnv: map[string]string{
+				"PATH":                "/bar1:/bar2:/foo1:/foo2:/init-path",
+				InitPathEnv:           "/init-path",
+				Key("fooProjectHash"): "/foo1:/foo2",
+				Key("barProjectHash"): "/bar1:/bar2",
+			},
+		},
+		{
+			projectHash:        "fooProjectHash",
+			nixEnvPath:         "/foo3:/foo2",
+			preservePathStack:  false,
+			expectedKeysLength: 3,
+			expectedEnv: map[string]string{
+				"PATH":                "/foo3:/foo2:/bar1:/bar2:/init-path",
+				InitPathEnv:           "/init-path",
+				Key("fooProjectHash"): "/foo3:/foo2",
+				Key("barProjectHash"): "/bar1:/bar2",
+			},
+		},
+		{
+			projectHash:        "barProjectHash",
+			nixEnvPath:         "/bar3:/bar2",
+			preservePathStack:  true,
+			expectedKeysLength: 3,
+			expectedEnv: map[string]string{
+				"PATH":                "/foo3:/foo2:/bar3:/bar2:/init-path",
+				InitPathEnv:           "/init-path",
+				Key("fooProjectHash"): "/foo3:/foo2",
+				Key("barProjectHash"): "/bar3:/bar2",
+			},
+		},
+	}
+
+	for _, testStep := range testSteps {
+		t.Run(
+			testStep.nixEnvPath, func(t *testing.T) {
+
+				// Push to stack and update PATH env
+				stack.Push(env, testStep.projectHash, testStep.nixEnvPath, testStep.preservePathStack)
+				env["PATH"] = stack.Path(env)
+
+				if len(stack.keys) != testStep.expectedKeysLength {
+					t.Errorf("Stack should have exactly %d keys but has %d keys. Keys are: %s",
+						testStep.expectedKeysLength, len(stack.keys), strings.Join(stack.keys, ", "))
+				}
+				for k, v := range testStep.expectedEnv {
+					if env[k] != v {
+						t.Errorf("env[%s] should be %s but is %s", k, v, env[k])
+					}
+				}
+			})
+	}
+}