apitest: semver_compare, add docu and default to "v0.0.0"

README.md

@@ -1850,6 +1850,10 @@ Example:
 
 ** oauth2_basic_auth** returns the authentication header for basic authentication for the given oauth client.
 
+## `semver_compare [version 1] [version 2]`
+
+**semver_compare** compares to semantic version strings. This calls https://pkg.go.dev/golang.org/x/mod/semver#Compare, so check there for additional documentation. If the version is `""` the version `v0.0.0` is assumed. Before comparing, the function checks if the strings are valid. In case they are not, an error is returned.
+
 # HTTP Server
 
 The apitest tool includes an HTTP Server. It can be used to serve files from the local disk temporarily. The HTTP Server can run in test mode. In this mode, the apitest tool does not run any tests, but starts the HTTP Server in the foreground, until CTRL-C in pressed.

go.mod

@@ -15,6 +15,7 @@ require (
 	github.com/spf13/cobra v0.0.5
 	github.com/spf13/viper v1.5.0
 	github.com/tidwall/gjson v1.3.4
+	golang.org/x/mod v0.4.2
 	golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be
 	golang.org/x/sys v0.0.0-20200223170610-d5e6a3e2c0ae // indirect
 )

pkg/lib/template/template_loader.go

@@ -432,6 +432,14 @@ func (loader *Loader) Render(
 			return string(b)
 		},
 		"semver_compare": func(v, w string) (int, error) {
+			if v == "" {
+				// empty version
+				v = "v0.0.0"
+			}
+			if w == "" {
+				// empty version
+				w = "v0.0.0"
+			}
 			if !semver.IsValid(v) {
 				return 0, errors.Errorf("version string %s is invalid", v)
 			}

test/semver/test_semver_compare.json

@@ -9,7 +9,8 @@
             "semver_easydb_patch": {{ semver_compare "v5.86.2" "v6.0.0" }},
             "semver_lt": {{ semver_compare "v5.1.2" "v6.0.0" }},
             "semver_eq": {{ semver_compare "v6.0.0" "v6.0.0" }},
-            "semver_gt": {{ semver_compare "v7.1.2" "v6.0.0" }}
+            "semver_gt": {{ semver_compare "v7.1.2" "v6.0.0" }},
+            "semver_eq2": {{ semver_compare "" "v0.0.0" }}
         }
     },
     "response": {
@@ -39,7 +40,12 @@
                 "semver_gt:control": {
                     "is_integer": true
                 },
-                "semver_gt": 1
+                "semver_gt": 1,
+
+                "semver_eq2:control": {
+                    "is_integer": true
+                },
+                "semver_eq2": 0
             }
         }
     }