Add test creating multiple plugins with load dependencies.

If we load plugins purely alphabetically, the 1st Zeek run in the test
will success while the 2nd will fail.

testing/btest/Baseline/plugins.plugin-load-dependency/output

@@ -0,0 +1,18 @@
+### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
+Testing::Plugin2 - Plugin2 provides a load dependency for Plugin1 and Plugin3 (dynamic, version 1.0.0)
+Testing::Plugin3 - Plugin3 has a load dependency on Plugin2 (dynamic, version 1.0.0)
+in Plugin2
+in Plugin3
+
+Testing::Plugin1 - Plugin1 has a load dependency on Plugin2 (dynamic, version 1.0.0)
+Testing::Plugin2 - Plugin2 provides a load dependency for Plugin1 and Plugin3 (dynamic, version 1.0.0)
+in Plugin1
+in Plugin2
+
+Testing::Plugin1 - Plugin1 has a load dependency on Plugin2 (dynamic, version 1.0.0)
+Testing::Plugin2 - Plugin2 provides a load dependency for Plugin1 and Plugin3 (dynamic, version 1.0.0)
+Testing::Plugin3 - Plugin3 has a load dependency on Plugin2 (dynamic, version 1.0.0)
+in Plugin1
+in Plugin2
+in Plugin2
+in Plugin3

testing/btest/plugins/plugin-load-dependency.zeek

@@ -0,0 +1,31 @@
+# @TEST-EXEC: mkdir 1
+# @TEST-EXEC: cd 1 && ${DIST}/auxil/zeek-aux/plugin-support/init-plugin -u . Testing Plugin1
+# @TEST-EXEC: cp -r %DIR/plugin-load-dependency/1 .
+# @TEST-EXEC: cd 1 && ./configure --zeek-dist=${DIST} && make
+
+# @TEST-EXEC: mkdir 2
+# @TEST-EXEC: cd 2 && ${DIST}/auxil/zeek-aux/plugin-support/init-plugin -u . Testing Plugin2
+# @TEST-EXEC: cp -r %DIR/plugin-load-dependency/2 .
+# @TEST-EXEC: cd 2 && ./configure --zeek-dist=${DIST} && make
+
+# @TEST-EXEC: mkdir 3
+# @TEST-EXEC: cd 3 && ${DIST}/auxil/zeek-aux/plugin-support/init-plugin -u . Testing Plugin3
+# @TEST-EXEC: cp -r %DIR/plugin-load-dependency/3 .
+# @TEST-EXEC: cd 3 && ./configure --zeek-dist=${DIST} && make
+
+# The following run will only work if Zeek loads plugin2 before plugin3 (which
+# by alphabetical loading will be the case)
+# @TEST-EXEC: ZEEK_PLUGIN_PATH=. zeek -b -N Testing::Plugin3 Testing::Plugin2 | grep -v Zeek:: | sort >> output
+#
+# @TEST-EXEC: echo >>output
+#
+# The following run will only work if Zeek loads plugin2 before plugin1 (which
+# by alphabetical loading will not be the case).
+# @TEST-EXEC: ZEEK_PLUGIN_PATH=. zeek -b -N Testing::Plugin1 Testing::Plugin2 | grep -v Zeek:: | sort >> output
+#
+# @TEST-EXEC: echo >>output
+#
+# Finally, try it with self-discovery of all three plugins too.
+# @TEST-EXEC: ZEEK_PLUGIN_PATH=. zeek -N | grep -v Zeek:: | sort >> output
+#
+# @TEST-EXEC: btest-diff output

testing/btest/plugins/plugin-load-dependency/1/src/Plugin.cc

@@ -0,0 +1,23 @@
+
+#include "Plugin.h"
+
+namespace btest::plugin::Testing_Plugin1 { Plugin plugin; }
+
+using namespace btest::plugin::Testing_Plugin1;
+
+extern void Plugin2_foo();
+
+zeek::plugin::Configuration Plugin::Configure()
+	{
+	zeek::plugin::Configuration config;
+	config.name = "Testing::Plugin1";
+	config.description = "Plugin1 has a load dependency on Plugin2";
+	config.version.major = 1;
+	config.version.minor = 0;
+	config.version.patch = 0;
+
+	printf("in Plugin1\n");
+	Plugin2_foo();
+
+	return config;
+	}

testing/btest/plugins/plugin-load-dependency/1/src/Plugin.h

@@ -0,0 +1,17 @@
+
+#pragma once
+
+#include <zeek/plugin/Plugin.h>
+
+namespace btest::plugin::Testing_Plugin1 {
+
+class Plugin : public zeek::plugin::Plugin
+{
+protected:
+	// Overridden from zeek::plugin::Plugin.
+	zeek::plugin::Configuration Configure() override;
+};
+
+extern Plugin plugin;
+
+}

testing/btest/plugins/plugin-load-dependency/2/src/Plugin.cc

@@ -0,0 +1,21 @@
+
+#include "Plugin.h"
+
+namespace btest::plugin::Testing_Plugin2 { Plugin plugin; }
+
+using namespace btest::plugin::Testing_Plugin2;
+
+void Plugin2_foo() {
+    printf("in Plugin2\n");
+}
+
+zeek::plugin::Configuration Plugin::Configure()
+	{
+	zeek::plugin::Configuration config;
+	config.name = "Testing::Plugin2";
+	config.description = "Plugin2 provides a load dependency for Plugin1 and Plugin3";
+	config.version.major = 1;
+	config.version.minor = 0;
+	config.version.patch = 0;
+	return config;
+	}

testing/btest/plugins/plugin-load-dependency/2/src/Plugin.h

@@ -0,0 +1,17 @@
+
+#pragma once
+
+#include <zeek/plugin/Plugin.h>
+
+namespace btest::plugin::Testing_Plugin2 {
+
+class Plugin : public zeek::plugin::Plugin
+{
+protected:
+	// Overridden from zeek::plugin::Plugin.
+	zeek::plugin::Configuration Configure() override;
+};
+
+extern Plugin plugin;
+
+}

testing/btest/plugins/plugin-load-dependency/3/src/Plugin.cc

@@ -0,0 +1,23 @@
+
+#include "Plugin.h"
+
+namespace btest::plugin::Testing_Plugin3 { Plugin plugin; }
+
+using namespace btest::plugin::Testing_Plugin3;
+
+extern void Plugin2_foo();
+
+zeek::plugin::Configuration Plugin::Configure()
+	{
+	zeek::plugin::Configuration config;
+	config.name = "Testing::Plugin3";
+	config.description = "Plugin3 has a load dependency on Plugin2";
+	config.version.major = 1;
+	config.version.minor = 0;
+	config.version.patch = 0;
+
+	printf("in Plugin3\n");
+	Plugin2_foo();
+
+	return config;
+	}

testing/btest/plugins/plugin-load-dependency/3/src/Plugin.h

@@ -0,0 +1,17 @@
+
+#pragma once
+
+#include <zeek/plugin/Plugin.h>
+
+namespace btest::plugin::Testing_Plugin3 {
+
+class Plugin : public zeek::plugin::Plugin
+{
+protected:
+	// Overridden from zeek::plugin::Plugin.
+	zeek::plugin::Configuration Configure() override;
+};
+
+extern Plugin plugin;
+
+}